•We examine steam stone fluids and smoke for trace metal analysis.•Further, we examine the use of standard ignition charcoal for trace metal content.•We compare the use of “e-charcoal” vs. standard ignition charcoal for trace metal content.•It is shown that for the standard charcoals the toxic trace metal burden is higher than with the “e-charcoals.”In the summer of 2009, the FDA obtained authority to regulate the manufacturing, distribution, and marketing of cigarettes and smokeless tobacco products. The Family Smoking Prevention and Tobacco Control Act was passed to reduce the trend of new users forming an addiction to tobacco before they were of the age to have an understanding of the toxic and even deadly consequences. However, non-conventional tobacco products, such as hookah tobacco, e-cigarettes, and other modified tobacco or tobacco-free alternatives are currently not regulated. On April 24th, 2014, the FDA announced they were planning on extending the agency's tobacco authority to cover additional tobacco products. Yet, not much is known about the hazards of these tobacco and potentially reduced exposure products (PREPs).Steam Stones are one alterative tobacco product where no quantitative information is available. These small pebble-like rocks contain no tobacco or nicotine and are coated in a viscous flavored fluid formulation consisting of glycerin, and are placed in a hookah head as an alternative to hookah tobacco. A total metal analysis with ICP–MS/MS was performed on the two originally marketed brands, Mya and Shiazo. The coatings of the stones underwent an initial hot water extraction for the purposes of determining the stones' metal composition for 26 metal targets. The toxic metals detected in both the Mya and Shiazo stones included trace levels of Cr, Ni, Cu, As, and Pb. This led to analyzing the toxic metals a smoker could potentially be exposed to during a 30 minute smoking session using both brands of steam stones and two different types of traditional smoldering charcoal. It was found that a smoker could inhale statistically similar quantities of Cr (between 12.2 ± 9.91 ng per smoking session to 1130 ± 776 ng per smoking session) and As (between 191 ± 30.1 ng per smoking session to 246 ± 101 ng per smoking session) when smoking one of four hookah head scenarios (scenario 1: Mya stones and Coco Nara charcoal, scenario 2: Mya stones and Fantasia charcoal, scenario 3: Shiazo stones and Coco Nara charcoal, and scenario 4: Shiazo stones and Fantasia charcoal).Although steam stones are marketed as free of nicotine, tar, carcinogens, and carbon monoxide, the use of traditional smoldering charcoal still exposes a user to these toxicants, including unacceptable amounts of harmful metals, such as Cr and As, despite the use of an alternative tobacco product. Notably, the use of electronic charcoal decreased the amount of toxic metals present in the smoke. Therefore, the smoke still contained relatively high levels of toxic metals, likely due to the use of traditional charcoal, which was previously quantified by ICP–MS/MS in our earlier paper [40].

Fluorescent dyes are widely used in the detection of labile (free or exchangeable) Zn2+ and Ca2+ in living cells. However, their specificity over other cations and selectivity for detection of labile vs. protein-bound metal in cells remains unclear. We characterized these important properties for commonly used Zn2+ and Ca2+ dyes in a cellular environment. By tracing the fluorescence emission signal along with UV-Vis and size exclusion chromatography-inductively coupled plasma mass spectrometry (SEC-ICP-MS) in tandem, we demonstrated that among the dyes used for Zn2+, Zinpyr-1 fluoresces in the low molecular mass (LMM) region containing labile Zn2+, but also fluoresces in different molecular mass regions where zinc ion is detected. However, FluoZin™-3 AM, Newport Green™ DCF and Zinquin ethyl ester display weak fluorescence, lack of metal specificity and respond strongly in the high molecular mass (HMM) region. Four Ca2+ dyes were studied in an unperturbed cellular environment, and two of these were tested for binding behavior under an intracellular Ca2+ release stimulus. A majority of Ca2+ was in the labile form as tested by SEC-ICP-MS, but the fluorescence from Calcium Green-1™ AM, Oregon Green® 488 BAPTA-1, Fura red™ AM and Fluo-4 NW dyes in cells did not correspond to free Ca2+ detection. Instead, the dyes showed non-specific fluorescence in the mid- and high-molecular mass regions containing Zn, Fe and Cu. Proteomic analysis of one of the commonly seen fluorescing regions showed the possibility for some dyes to recognize Zn and Cu bound to metallothionein 2. These studies indicate that Zn2+ and Ca2+ binding dyes manifest fluorescence responses that are not unique to recognition of labile metals and bind other metals, leading to suboptimal specificity and selectivity.

The use of water pipes or hookahs to smoke tobacco formulations has gained great popularity among young people around the world, but the potential health hazards have not yet been adequately evaluated. The complexity of a multi component hookah apparatus, compared with cigarettes and cigars, makes it difficult to study under laboratory conditions. For this reason the detailed study of its components simplify the task. In this study the charcoal, which is traditionally used as the heat source, was analyzed for metal content before and after combustion. Sixteen different hookah charcoals were analyzed representing different compositions and manufacturing processes as well as different geographic origins. ICP-MS was used to measure 24 elements: Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th, U. The total concentration ranges of toxic elements in native (un-burned) charcoals were: arsenic 14.8–10300 ng g−1, cadmium 3.3–2100 ng g−1, and lead 95.2–55600 ng g−1. The mass-loss-corrected content of elements in combusted charcoals shows that most of the metals remain in the ash, with iron, cadmium and lead as exceptions. Because of the high content of arsenic in some samples an extraction and speciation method was developed to quantify four chemical forms of arsenic. Nitric acid, and phosphoric acid were evaluated as extractants used in a heating block, and ascorbic acid was used to minimize oxidation of inorganic As3+ to As5+. Anion exchange chromatography coupled to ICP-MS was used to carry out the separation and quantification of arsenic species. The best conditions in terms of extraction efficiencies and species conservation were 1.2 mol L−1 H3PO4, with 0.2 mol L−1 ascorbic acid. As5+ was the dominant arsenic species in charcoal. Concentrations ranged from 0.08–2.42 mg kg−1, for As3+ and 0.46–8.36 mg kg−1 for As5+. The results show high variation depending on the sample origin and composition. The possibility of volatile cadmium and lead contributions to the primary and second hand smoke by the charcoal are suggested and the high levels of arsenic suggest that for certain charcoals there may be more hazard from them than from the tobacco formulation.

The effect of selenium on modulating arsenic cytotoxicity is well known in mammals, but not well understood. Cell cytotoxicity and reactive oxygen species (ROS) changes were performed in combinations of As(III) and selenomethionine (SeMet) toxic mixes on, HEK293, human kidney cells. Cell growth is readily restored from 20% to 60% when switching from 30 μM As(III) as toxin to a mix of 30 μM As(III) and 100 μM SeMet. As(III) alone triggers ROS formation, primarily hydrogen peroxide, in a concentration dependent manner as observed through changes in the fluorescence from 2′,7′-dichlorofluorescein diacetate. Importantly, SeMet induces lower ROS levels at the same concentrations used to modulate As(III) cytotoxicity (IC50). Elevated ROS is important to As(III) cytotoxicity and minimizing it is essential to the SeMet modulating function. Changes in cell signaling, through analysis of signaling changes via differential protein phosphorylation to uncover molecular level changes occurring in HEK293 human kidney cells as SeMet modulates the As(III) cytotoxicity. To discover changes in the phosphoproteome, cells were incubated under three conditions: 30 μM As(III), 100 μM SeMet, and 30 μM As(III) + 100 μM SeMet. After total protein isolation the three samples were separated into fractions using size exclusion chromatography by detecting 31P+. Each sample was analyzed for the phosphorylated peptides by enzymatic digestion, selective enrichment of phosphorylated peptides via TiO2, followed by nanoLC-ESIMS. Phosphorylated proteins unique to the As(III)–SeMet mixture were then identified. The molecular level changes to the cells show uniquely that the As(III)–SeMet mixture details proteins involved in ROS detoxification, cell cycle arrest, and protein/DNA damage. This study shows that SeMet not only lowers the total amount of ROS in a cell but also confers upon HEK293 cells the ability to detoxify. Thus, SeMet is not only a potent antioxidant in this system, but induces molecular changes that confer survival.

•Water-soluble protein fraction of Brazil nuts contains Cu-containing proteins.•A Cu-containing peptide in tryptic digest was identified by MALDI MS using modified isotope pattern.•A tentative formula, [M+Cu(I)]+, was proposed for the Cu-containing peptide based on MALDI MS data.Metalloproteomics (studying metal-containing proteins by proteomics approach) is an important subset of any proteomics study. Metals existing in different isotopes in nature impart a “finger-print” isotope pattern to the metal-containing polypeptide, which is different from the normal isotope pattern of a polypeptide. This study was directed to identify Cu-containing polypeptide generated by tryptic digestion of Cu-containing protein in Brazil nuts (a real-world sample) using characteristic isotope pattern of Cu-containing polypeptides under acidic conditions by MALDI MS. A Cu-containing polypeptide at m/z 1438.12 and its protonated apopeptide at m/z 1376.21 were identified and a tentative formula for the Cu-containing polypeptide, [M+Cu(I)]+, was proposed based on MALDI spectral characteristics. Presence of Cu-containing polypeptides in tryptic digest was further supported by SEC-ICPMS (size-exclusion chromatography coupled with inductively coupled plasma mass spectrometry) profiling of tryptic digests of Cu-containing proteins. Cytochrome C was used as a model protein to investigate the feasibility of using characteristic isotope pattern in identifying metal-containing polypeptides under standard experimental conditions (denaturing, reduction, alkylation and acidic matrix) employed in proteomics. Additionally, Cu-containing proteins in water-soluble protein fraction of Brazil nuts was profiled by SEC-ICPMS.

•HEK 293 cells cultured with selenomethionine produce Se-containing proteins.•Multiple chromatographies with ICPMS and ESIMS detections led to these results.•Se-containing proteins were identified with more abundant overlapping S-analogs.Our previous studies using HeLa and HEK 293 cells demonstrated that selenomethionine, SeMet, exerts more of an antagonistic effect on arsenic than other selenium species. These studies attributed the antagonistic effect of SeMet to decreased levels of reactive oxygen species, ROS, changes in protein phosphorylation and possible incorporation of SeMet into proteins. The present study employs a metallomics approach to identify the selenium-containing proteins in HEK 293 cells raised with SeMet. The proteins were screened and separated using two dimensional high performance liquid chromatography (HPLC)–inductively coupled plasma mass spectrometry (ICPMS), size exclusion chromatography (SEC) and reversed-phase chromatography (RPC). The Se-containing proteins were identified by peptide mapping using nano-HPLC–Chip–electrospray ionization mass spectrometry (ESIMS).

Stroke is the leading cause of disability in the USA. Rapid, reliable diagnosis via a point-of-care blood test may facilitate earlier treatment to reduce disability. We have recently reported detailed methods of chromatographic separations of plasma samples coupled with nanoESI-ion trap a list of proteins which are viable candidates for further investigation as stroke biomarkers.

Stroke is the leading cause of adult disability, worldwide. Metalloproteins and metals play key roles in epigenetic events in living organisms, including hypertension, the most important modifiable risk factor for stroke. Thus, metalloproteins may be important target biomarkers for disease diagnosis. The primary goal of this study was to assess metal containing proteins in blood plasma, detected by ICP-MS, followed by ESIMS for peptide/protein identification. We then compared the relative concentration differences between samples from patients with ischemic stroke, hemorrhagic stroke and stroke mimics. In 29 plasma samples (10 stroke mimics, 10 ischemic stroke and 9 hemorrhagic stroke patients) previously collected from patients who presented to the University of Cincinnati Emergency Department within 12 hours of symptom onset for a plasma banking project. For the metal associated protein study, Mg, Mn, Cu, Se concentrations were statistically different when compared between stroke mimics vs. ischemic stroke patients and ischemic stroke patients vs. hemorrhagic stroke patients. Pb concentrations were statistically different when compared between stroke mimics vs. ischemic stroke patients and Mo levels were statistically the same among the three groups. In addition, we also report concentration levels and preliminary correlation studies for total elemental analysis among the three sets of patients. This pilot study demonstrates that mass spectrometry methods may be highly valuable in detecting novel stroke biomarkers in blood plasma. Expanded studies are warranted to confirm these findings.

Cerebral vasospasm (CV) following subarachnoid hemorrhagic stroke affects more than one million people each year. The etiology and prevention of CV is currently of great interest to researchers in various fields of medical science. More recently, the idea that selenium could be playing a major role in the onset of cerebral vasospasm has come into the spotlight. This study focused on using newly established metallomics techniques in order to explore the proteome associated with CV and if selenium might affect the discovered proteins. Size exclusion chromatography coupled to inductively coupled plasma mass spectrometry, along with LC-MALDI-TOF/TOF were both essential in determining protein identifications in three different sample types; a control (normal, healthy patient, CSF control), SAH stroke patients (no vasospasm, CSF C) and SAH CV patients (CSF V). The results of this study, although preliminary, indicate the current methods are applicable and warrant further application to these clinically important targets.

In this initial study, the concentrations of eighteen elements (Na, K, Mg, Ca, Al, Fe, V, Cr, Mn, Ni, Cu, Zn, Se, Mo, As, Cd, Sb and Pb) in 12 hookah tobacco formulations (mo'assel) were studied by ICPMS. Eight of these were formulated in the United States, and four were from the Middle East. The analyses were made from two of the hookah compartments; as homogenized material of the hookah samples as received and by separating the received samples into the actual tobacco and a hot water extract that removed as much of the other formulation substances as possible. The extractable portion that represents up to 50% in mass of the total hookah sample is made up of honey/molasses, glycerin, colorants and flavorings, but this study shows the hot water extract to be relatively free of toxic elements. The elemental ranges found for the homogenized hookah mixtures are as follows: V, 0.03–0.16 μg g−1; Cr, 0.15–0.37 μg g−1; Mn 8.82–17.2 μg g−1; Ni, 0.14–0.64 μg g−1; Cu, 0.93–5.67 μg g−1; Zn, 3.51–5.62 μg g−1; As, 0.01–0.04 μg g−1; Se, 0.002–0.014 μg g−1; Mo, 0.05–0.13 μg g−1; Cd, 0.10–0.27 μg g−1 and Pb, <0.001–0.07 μg g−1. Given the very small fraction of trace metals in the extract, most of the metals are contained in the tobacco leaves. It was found that the major variation in the concentrations owe to the geographic production regions; namely the USA and the Middle East. A principal component analysis was performed as an explorative tool, and a good separation was found, when grouping according to preparation by geographic production region. Based on these results the average mass of the more toxic elements (As, Cd, Cr and Pb) present in a hookah smoking portion of about 15 g, is smaller than that contained in a normal cigarette. However, before any true comparisons can be made on the differences between the hookah formulations and actual dryer tobaccos, the temperature at which the smoke is produced, the length of time per smoking session, any possible metal contamination from the apparatus and contamination from the charcoal used to ignite the hookah formulation must be taken into account.

Our previous study found that high-molecular-weight selenium (Se) species make up 82% of the total Se in the bean of Se-enriched soybean plants (Chan et al. 2010, Metallomics, 2(2): p. 147–153). The Se species have been commonly seen in other plants in addition to soybean, but their identities remain unresolved. The present study employs a multi-technique metallomics approach to characterize the proteins containing Se in the beans of Se-enriched soybean plants. Two main categories of proteins, maturation proteins and protease inhibitors, were found in Se-containing high-performance liquid chromatography (HPLC) fractions. The proteins were screened by two-dimensional HPLC-inductively coupled plasma mass spectrometry, size-exclusion chromatography, and anion-exchange chromatography, and the Se-containing fractions were then identified by peptide mapping using HPLC-Chip-electrospray ion trap mass spectrometry. Based on the belief that Se goes into proteins through non-specific incorporation, a new method was designed and applied for the Se-containing peptide identification. The Se-containing peptide KSDQSSSYDDDEYSKPCCDLCMCTRS, part of the sequence of protein Bowman–Birk proteinase isoinhibitor (Glycine max), was found in one of the Se-containing fractions. The nutritional value of the Se-containing proteins in Se-enriched soybeans will be an interesting topic for the future studies.

Although the proteome and genome of bacteriophages are well developed, there is little knowledge about metals and their interactions with the phages, even though metals have been observed in stabilizing phage particles. With expanding studies of phage display and its promising applications, metalloprotein investigations in the bacteriophage areas are necessary to understand whether or not metalloproteins are included in the viral coat proteome. Since these virus studies are still in their infancy, lambda phage was chosen due to its high metal-binding potential as suggested by the cysteine/methionine rich proteins in the viral coat. After large-scale preparation and further purification of lambda phage according to standard protocols, state-of-the-art metallomics techniques via combinations of chromatographies and mass spectrometries were utilized for screening metal-associated species in lambda phage. The lambda phage sample was first separated using non-denaturing size exclusion chromatography with selective metal detection by ICPMS for screening associated metals and generating size distribution fractions for the various metal species, some of which include metalloproteins. Various molecular size distribution patterns were exhibited for the metals detected, Mn, Fe, Co, Ni, Cu and Zn, at different molecular weight ranges. On the other hand numerous other metals were not associated with the coat proteins, as they were not detected in the different molecular weight fractions. Further identification for putative metallopeptides and metalloproteins was accomplished by collecting various metal species’ fractions offline and subsequently analyzing tryptically-digested fractions via nanoLC-Chip-ESI-MS. By searching appropriate MS databases with both Spectrum Mill and MASCOT search engines, the main capsid protein, gpE, a capsid decoration protein, gpD, and main tail component protein, gpV, were found and are known for associations with the detected transition metals. These findings will likely provide valuable information for lambda phage engineered applications.

Although arsenic toxicity is well known, little is known of how it exerts its effects at the proteome level. Protein phosphorylation is an important post-translational modification in the regulation of cell signaling. Despite the importance of protein phosphorylation, the identification and characterization of phosphorylated proteins, as influenced by interaction between arsenic and selenium species have not been fully studied. The aim of this study is to identify phosphorylation in arsenic toxified cells, with and without selenium present. Here, we identify the phosphorylated proteins related to post translational modifications (PTMs) after inorganic arsenic (iAs) and selenomethionine (SeMet) were inoculated together with HEK293 human kidney cells. In this study, using TiO2-based nanoLC-phosphochip® coupled to ESI-MS we observed phosphorylated peptide enrichment and significant reduction in sample complexity. The identification of phosphorylated proteins in highly complex digests of cell lysate were markedly different with As toxification only, or when in the presence of SeMet. Several phosphorylation sites and proteins are identified using Spectrum Mill and Mascot protein data base search engines. Cytotoxicity studies showed that SeMet significantly reduces the cytotoxic effect of iAs in HEK293 cells, while inorganic selenium did not.

Owing to recent studies which showed that Se supplementation in the diet can reduce the risk of several forms of cancer, efforts have been directed to identify anticarcinogenic activity in Se compounds from natural sources with the objective of using those as food supplements. As a part of a continuing research project directed at identifying Se-containing species in food stuffs, the distribution of selenium-containing proteins in water-soluble protein fraction of seeds of Bertholletia excelsa H.B.K., which typically have a high Se content, was studied under non-denaturing conditions and the effectiveness of protein fractional precipitation by ammonium sulfate was investigated with the objectives to preconcentrate the protein(s) of interest and to reduce the matrix complexity. By SEC–ICPMS, Se-containing proteins (selenoproteome with some additional proteins) were found demonstrating the usefulness of ICPMS as an “on-line assay” in sub-proteomics investigations. Fractions with Se-containing proteins, collected from SEC, were tryptically digested and tryptic digests were analyzed by MALDI-TOF-reflectron MS and capLC–ESI-QTOF-MS. Isotope patterns which are different from the typical isotope patterns of peptides containing C, H, O, N and S were used to identify selenium-containing peptides in the digests. Observed isotope patterns were slightly different from the predicted isotope patterns and partial deamidation of selenium-containing peptides is suggested to explain the modified isotope pattern. To our knowledge, this is the first report of the effect of partial deamidation of selenium-containing peptides on the observed selenium isotope pattern, although the evidence is indirect. According to the SEC–ICPMS study, Se-containing proteins in water-soluble protein fraction of Bertholletia excelsa H.B.K. seeds can be divided into two main sub-groups-high molecular weight Se-containing proteins and low molecular weight Se-containing proteins. LC–ESI-MS and MS/MS analysis of tryptic digest of low-molecular weight Se-containing proteins identified 2S albumins, which are rich in methionines; therefore, with a high probability of non-specific selenomethionine incorporation—as the proteins present in that fraction.Graphical abstractIsotope pattern changes showing the effect of deamidation from the normal form (a), C80H135N19O20Se, to the deamidated form (b), C80H134N18O21Se.Research highlights▶ Importance of ICPMS as an “on-line assay” in selenoproteomics research. ▶ Distribution of Se-containing proteins in water-soluble protein fraction of Brazil nuts. ▶ Slightly modified Se-isotope pattern owing to the occurrences of partial deamidation. ▶ Identified proteins S14946, CAA00789, A25802, BAA96554, Q9LRC2, S14947, Q84ND2_BEREX.

Cerebral vasospasm (CV) refers to physical narrowing of brain cerebral arteries due to over-contraction of the arterial wall, which often arises following a subarachnoid hemorrhage (SAH). CV is frequently associated with poorer outcomes in those patients. Between the ictus of SAH and its CV complication, there is a 3–7 days delay, which provides a time window to predict and possibly prevent the onset CV. Since the precise pathomechanism of CV is still unclear and approaches for predicting it are inefficient, more effective ways of predicting CV need to be developed. As a protective nourishing fluid flows through the subarachnoid space, cerebrospinal fluid (CSF) closely relates to the health states of the central nervous system (CNS). Analysis of CSF can provide invaluable information to diagnose, treat and prevent diseases of the CNS because of its relatively direct representation of events in the brain. Therefore, we assume that the components in CSF and their alterations may reflect the state of aneurismal SAH and the development of vasospasm. In this study, three types of CSF from healthy control, and patients who suffered SAH and its complication, CV, were investigated via two-dimensional separations in combination with elemental and molecular mass spectrometry detection for the identification of elemental species. Size exclusion chromatography (SEC) was initially used with selective metal detection by inductively coupled plasma mass spectrometry (ICPMS) for characterizing size distribution of metal species. Various molecular distribution patterns were exhibited at different metal detection points (Fe, Ni, Cu, Zn and Pb). Further identification of possible metallopeptides and metalloprotein in tryptic digested fractions from the three sample types were made via reverse phase (RP)-Chip and electrospray mass spectrometry (MS) in combination with the Spectrum Mill data base search engine accessing appropriate data bases. Comparisons were generated to show suggested protein similarities or differences across the three CSF sample types. Six protein families with possible protein markers were further identified, and may be considered as possible focus areas for discovering valuable biomarkers to preclude the debilitating or deadly vasospasm.

Soybean (Glycine Max) plants were grown in soil supplemented with sodium selenite. A comprehensive selenium profile, including total selenium concentration, distribution of high molecular weight selenium and characterization of low molecular weight selenium compounds, is reported for each plant compartment: bean, pod, leaf and root of the Se-enriched soybean plants. Two chromatographic techniques, coupled with inductively coupled plasma mass spectrometry (ICPMS) for specific selenium detection, were employed in this work to analyze extract solutions from the plant compartments. Size-exclusion chromatography revealed that the bean compartment, well-known for its strong ability to make proteins, produced high amounts (82% of total Se) of high molecular weight selenospecies, which may offer additional nutritional value and suggest high potential for studying proteins containing selenium in plants. The pod, leaf and root compartments primarily accumulate low molecular weight selenium species. For each compartment, low molecular weight selenium species (lower than 5 kDa) were characterized by ion-pairing reversed phase HPLC-ICPMS and confirmed by electrospray ionizationion trap mass spectrometry (ESI-ITMS). Selenomethionine and selenocystine are the predominant low molecular weight selenium compounds found in the bean, while inorganic selenium was the major species detected in other plant compartments.

Kale (Brassica oleracea A.) can accumulate high concentrations of Se, as well as lutein and β-carotene, which have important human health benefits and possess strong antioxidant properties. In the present study, kale plants were cultivated in soil supplemented with sodium selenite or sodium selenate. The plants accumulated over 20 times higher concentration of selenium in the selenate-enriched soil compared with selenite-enriched soil. Selenium accumulation did not suppress the plant's uptake of the essential metals, Fe, Cu and Zn. Speciation of selenium in the plant was performed via size-exclusion chromatography and ion-pairing reversed phase chromatography using inductively coupled plasma mass spectrometry (ICPMS) and nano-electrospray ion trap mass spectrometry (nanoESI-ITMS) for detection. In ion-pairing reversed phase chromatography, 0.02% HFBA was found to facilitate separating the selenium metabolites without hampering ESI-ITMS ionization. MS2/MS3 spectra were successfully obtained for identification of Se-methylselenocysteine (MeSeCys). MeSeCys was the prominent selenium metabolite formed in kale, which has been suggested as a chemopreventive food supplement. The Se species in leaf are significantly different from those in stem. The leaf shows higher content of high molecular weight selenium than the stem, while the stem produced higher amounts of MeSeCys than the leaf, indicating the metabolism to MeSeCys competes with the production of high molecular weight selenium forms. The plant leaf, when supplemented with Se(IV), contained the highest amount of high molecular weight selenium (49%) as well as the lowest amount of MeSeCys (4%).

The objective of this review is to note recent novel developments and applications rather than to be comprehensive. We intend to explore instrumental advances that demonstrate enhanced analytical capability. Along these same lines, there have been a number of recent papers coupling solid phase microextraction with GC-ICPMS and these will be discussed. Not only does this preparation technique present several advantages, such as environmental friendliness through reduced solvent consumption, it also lends itself to easy incorporation into a GC analytical scheme. Finally, new explorations in the analysis of the traditional metal species, as well as novel applications of species of nontraditional elements, are presented.

Developing a reliable and robust trace level method for organophosphates in the presence of relatively high inorganic phosphate is an area of interest for further method development. Since the advent of collision/reaction cell technology, inductively coupled plasma mass spectrometry (ICPMS) has been used with a variety of sample types for elemental phosphorus detection at m/z = 31. However, with many samples inorganic phosphate may be orders of magnitude higher than organophosphates, presenting a major interference to quantification. Therefore, removal of inorganic phosphate to levels low enough to minimize the interference would prove beneficial for more effective organophosphate analyses. In this study, applicable to most organophosphate containing samples, the illustration is to nerve agent degradation products as they might contaminate food and environmental systems after their initial formation. Calcium chloride was chosen as a coagulant mix and ammonium hydroxide was chosen to adjust the pH in order to remove inorganic phosphate at the sample preparation step. High performance liquid chromatography (HPLC) coupled with ICPMS was utilized for analysis. The results show that inorganic phosphate, at concentrations as high as 10000 µg mL−1, can be sufficiently removed by precipitation with calcium at pH > 9 while the organophosphorus chemical warfare agent degradation products, CWADPs, remain intact. Applications to apple juice and cola drink indicate that this method is suitable for more complex matrices containing relatively high levels of inorganic phosphate.

Significant effort has been devoted to studying the mutually protective effect of selenium and mercury in mammals. However, a limited number of studies have investigated the potential selenium–mercury antagonism in plants, which may prove informative for ultimate phytoremediation purposes. In this study, the Allium fistulosum, green onion, was used to investigate the metabolic fate of mercury in conjunction with or exclusion of selenium. The plants were grown in perlite media and supplemented with sodium selenite and mercuric chloride. Total elemental analysisviamicrowave digestion and inductively coupled plasma mass spectrometry (ICPMS) detection, showed that the A. fistulosum accumulated 50 times more mercury than selenium, both elements were predominately sequestered in the root fraction, and a mutual antagonism was observed. Size exclusion and capillary reversed phase chromatography were coupled to ICPMS to investigate the plant root and leaf extracts. The data suggest a possible selenium–mercury association in a protein containing macromolecule, which is not further metabolized upon translocation to the aerial plant regions. The selenium–mercury association may be formed by combining small selenium molecules, which are normally translocated to the aerial plant regions. Data from enzymatic and acid hydrolysis suggests formation of stable mercury metabolites in the plant when supplemented in conjunction with selenium.

Se-enriched rice was prepared by foliar fertilization. In the present work, speciation and distribution of Se in Se-enriched rice and non-supplemented rice was evaluated by ion-paring reversed phase (IP-RP) and strong anion-exchange (SAX) chromatography coupled with inductively coupled plasma mass spectrometry (ICPMS) detection. Three extraction procedures: water extraction, acid extraction (0.1 M HCl) and enzymatic hydrolysis were studied with a combination of protease XIV and amylase with ultrasonic bath and the latter was found to be optimal for the extraction of selenospecies. The chromatograms obtained revealed that the major selenospecies found in Se-enriched rice was selenomethionine (SeMet), which was further identified by nanoelectrospray ionization, ion trap mass spectrometry (nano-ESI-ITMS). Approximately 86.9% of the total Se in the Se-enriched rice extract was SeMet, while only 26.7% of non-supplemented rice extract was due to SeMet. Moreover, nearly 60% of inorganic Se in the form of SeIV was present in the non-supplemented rice, while only 6.8% of inorganic Se as SeIV and SeVI was found in Se-enriched rice extract with minor selenocystine (SeCys2) and trace selenomethionine selenoxide (SeOMet) present. The results proved that SeMet was efficiently extracted by the enzymatic hydrolysis without oxidization. The high SeMet concentrations of Se-enriched rice indicate a high inorganic to organic conversion when Se enrichment was carried out by foliar application. Since SeMet is a readily bioavailable Se species for animals, Se-enriched rice could be considered for supplementation in Se poor geographical regions.

A procedure for the determination of 10 organophosphates, used as flame retardants and plasticizers, in sediment samples is presented. Microwave-assisted extraction (MAE) and gas chromatography with inductively coupled plasma mass spectrometry (GC–ICP-MS) were used for sample preparation and analytes determination, respectively. Influence of different variables on the performance of extraction and determination processes is thoroughly discussed. Temperature, type and amount of organic solvent showed a major effect on the yield of MAE. Regarding GC–ICP-MS detection, the combination of pulsed splitless injection with low radio frequency (rf) power, hard extraction conditions (referred to lens voltage) and addition of nitrogen (0.03 L min−1) to the argon plasma provided the best sensitivity. Under final working conditions, recoveries between 78% and 105%, for samples spiked at different concentration levels, and limits of quantification from 2 to 4 ng g−1 were achieved. Analysis of unspiked sediments confirmed the excellent selectivity of the proposed method for real-life polluted sample analysis.

Sulfur mustard (HD), bis(2-chloroethyl)sulfide, is one of a class of mustard agents which are chemical warfare agents. The main chemical warfare hydrolysis degradation products of sulfur mustards are: thiodiglycol, bis(2-hydroxyethylthio)methane, 1,2-bis(2-hydroxyethylthio)ethane, 1,3-bis(2-hydroxyethylthio)propane, and 1,4-bis(2-hydroxyethylthio)butane. The aim of this study is to identify these five hydrolysis degradation products utilizing reversed-phase high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) for element-specific sulfur detection using a collision/reaction cell and electrospray ionization mass spectrometry to confirm the identification. To date, this is the first study utilizing ICP-MS with 32S element-specific detection for the analysis of vesicant chemical warfare agent degradation products.

Trace metal analysis has been long regarded as one of the principle tasks in areas of chemical analysis. At the early stage of instrumental development, total concentration was assessed in a variety of samples, yielding results, among others, for environmental, biological, and clinical samples. With the power of newer analytical techniques, such as inductively coupled plasma mass spectrometry (ICP-MS), accurate quantitative results can now be obtained at ultra-trace levels not only for metals, but also for metalloids and several non-metals. Even though the importance of trace elements in many biological processes is widely accepted, the elucidation of their biological pathways, understanding specific biological functions, or possible toxicological aspects is still a challenge and a driving force to further develop analytical methodology. Over the past decades, the scientific interest has moved from total element determination to include speciation analysis, which provides quantitative information of one or more individual element species in a sample. More recently, metallomics has been introduced as a more expanded concept, in which the global role of all metal/metalloids in a given system is considered. Owing to the multi-elemental focus of metallomics research, the use of ICP-MS becomes indispensable. Furthermore, considering the biological role of metals/metalloids and the use of elements as internal or external molecular tags, epigenetics should be considered as an important emerging application for metallomics studies and approaches. Among a variety of epigenetic factors, essential nutrients, but also environmental toxins, have been shown to affect DNA methylation, modification of histone proteins, and RNA interference, all of them being implicated in cancer, cardiovascular disease, and several inherited conditions. Recent studies suggest that epigenetics may be a critical pathway by which metals produce health effects. In this Trends article, the basic epigenetic concepts are introduced, followed by the early applications of ICP-MS classified as: (i) detection of 31P as a natural element tag for DNA, (ii) analysis of DNA adducts with metal-based drugs, (iii) element species as epigenetic factors.

Cerebrospinal fluid (CSF) has frequently been studied to explore the total metal concentrations in patients with neurodegenerative diseases. Some examples of neurologic diseases include but are not limited to intracerebral hemorrhage, intraventricular hemorrhage, traumatic brain injury, subarachnoid hemorrhage and hydrocephalus. In this study, however, a comprehensive approach was begun using metallomics methods. First, two molecular weight cutoff filters were used to separate CSF constituents by molecular weight. The remaining CSF was then separated with capillary liquid chromatography/normal bore liquid chromatography and analyzed with inductively coupled mass spectrometry (ICPMS). With this ICPMS screening, a possible iron associated protein was suggested by nanoliquid chromatography-CHIP/ion trap mass spectrometry (nanoLC-CHIP/ITMS) identification in conjunction with a Spectrum Mill database search. In this preliminary study, three different types of pooled CSF were partially characterized by their metal (Pb, Mg, Zn, Fe and Cu) containing species with suggestions for fuller studies. Chemical ‘differences’ in the CSF and metal constituents suggests some utility in this analysis for understanding some of the complications observed following subarachnoid hemorrhage.

An initial study of protein phosphorylation in human cerebral spinal fluid (CSF) is described. CSF is an important body fluid for study of proteins and metabolites and may lead to the ultimate development of molecular markers to predict neurological diseases or their complications, such as in the case of hemorrhagic stroke. The use of capillary liquid chromatography coupled to inductively coupled plasma mass spectrometry (capLC−ICPMS) for screening using 31P as the internal elemental tag atom at ultratrace levels, in combination with molecular mass spectrometry using Spectrum Mill and MASCOT database search engines for peptide identification, is a novel approach in its application to CSF relevant phosphopeptides and phosphorylated proteins. CapLC−ICPMS combined with nano liquid chromatography electrospray ionization, ion trap mass spectrometry (nanoLC−CHIP/ITMS), was utilized for initial experiments with CSF. Specific low-level screening for 31P containing compounds is accomplished, and nanoLC−CHIP/ITMS provided the corresponding peptide information and subsequent protein identifications. The fractions containing 31P from screening by the capLC−ICPMS were collected offline and analyzed separately with nanoLC−CHIP/ITMS. Synthetic phosphopeptides were used to test the method and to estimate lowest quantifiable limits for phosphorus. Tryptically digested β-casein was then used to demonstrate the viability of the methodology for the complex CSF matrix from hemorrhagic stroke patients while also analyzing for native phosphopeptides in the CSF.

The following work presents the exploration of three chromatographic separations in combination with inductively coupled plasma mass spectrometry (ICP-MS) for the analysis of chemical warfare agent degradation products (CWADPs). The robust ionization of ICP is virtually matrix independent thus enabling the examination of sample matrices generally considered too complicated for analysis by electrospray ionization (ESI) or atmospheric pressure chemical ionization MS with little to no sample preparation. The analysis was focused on detecting CWADPs in food matrices, as they present possible vehicles for terrorist contamination. Due to the specific detection of 31P by ICP-MS, resolution of analytes of interest from other P-containing interferences (H3PO4) was a crucial part of each separation. Up to 10 CWADPs were separated in the presence of H3PO4 with detection limits in the low part per billion levels using the methods described. Additionally, one method was tailored to be compatible with both ICP-MS and ESI-MS making structural verification possible.

A reversed-phase high-performance liquid chromatographic technique was developed to separate cadmium–phytochelatin complexes (Cd-PC2, Cd-PC3, and Cd-PC4) of interest in the plant Arapidopsis thaliana. High-performance liquid chromatography (HPLC) was coupled to an inductively coupled plasma mass spectrometric (ICP-MS) system with some modification to the interface. This was done in order to sustain the plasma with optimum sensitivity for cadmium detection in the presence of the high methanol loads used in the gradient elution of the reversed-phase separation. The detection limits were found to be 91.8 ng l−1, 77.2 ng l−1 and 49.2 ng l−1 for Cd-PC2, Cd-PC3, and Cd-PC4 respectively. The regression coefficients (r2) for Cd-PC2 to Cd-PC4 detection ranged from 0.998 to 0.999. The method was then used to investigate the occurrence and effect of cadmium–phytochelatin complexes in wild-type Arabidopsis and a phytochelatin-deficient mutant cad1-3 that had been genetically modified to ectopically express the wheat TaPCS1 phytochelatin synthase enzyme. The primary complex found in both wild-type and transgenic plants was Cd-PC2. In both lines, higher levels of Cd-PC2 were found in shoots than in roots, showing that phytochelatin synthases contribute to the accumulation of cadmium in shoots, in the Cd-PC2 form. Genetic modification did, however, impact the overall accumulation of Cd. Transgenic plants contained almost two times more cadmium in the form of Cd-PC2 in their roots than did the corresponding wild-type plants. Similarly, the shoot samples of the modified species also contained more (by 1.6 times) cadmium in the form of Cd-PC2 than the wild type. The enhanced role of PC2 in the transgenic Arabidopsis correlates with data showing long-distance transport of Cd in transgenic plants. Targeted transgenic expression of non-native phytochelatin synthases may contribute to improving the efficiency of plants for phytoremediation.

In this study, three liquid chromatographic techniques were employed to better understand selenium species distribution in Chives (Allium schoenoprasum) separately grown in three different supplementation media Se(IV), Se(VI), and SeMet. The highest selenium accumulation up to 700 μg Se g−1 was observed in the case of the Se(VI)-enriched samples on the basis of total selenium measurements. Size-exclusion chromatography (SEC-HPLC) was performed for investigation of selenium containing proteins in chives. For speciation of selenium containing amino acids, reversed-phase ion-pairing chromatography (RP-IP-HPLC) and for enantiomeric separations, a crown ether column was used. In all three cases online detection with inductively coupled plasma mass spectrometry was performed for selenium specific detection. Two extractions (perchloric acid–ethanol and enzymatic) were carried out on chive samples. Speciation analysis on the chives grown in three different media revealed that selenium distribution among different forms of amino acids in the sample strongly depends on the type of enrichment employed. Enrichment with Se(VI) leads to accumulation of selenium in inorganic forms, while in case of Se(IV) and SeMet-enriched samples, methyl-selenocysteine and selenocystine were found to be present. Not surprisingly, chiral speciation revealed the presence of the l-enantiomeric forms of selenoamino acids in the sample. The major enantiomer found in the perchloric acid–ethanol extracts was l-MeSeCys, while in the enzymatic extracts l-SeMet was also detected.

This work focuses on phytochelatins (PCs) in plants chronically exposed to low or moderate metal concentrations in soil, which commonly occurs in natural environments. The original approach was to evaluate PCs in nopal (Opuntia ficus) in relation to the plant and soil levels of Cd, Pb, Cu and Ag. These four metals were selected because of their known capability to induce PCs in plants and also because of their abundance in the region of Guanajuato (Mexico), where the nopal plants were collected. ICP-MS determination of metals in nopal roots, stems and in soil fractions provided information relevant to their bioavailability in soil as well as their uptake by nopal. In search of a possible relationship between the parameters measured, correlation analysis was carried out (Cd was not considered owing to its low levels found in the plant tissues). The results obtained indicate that sequential metal leaching from soil does not always provide direct information on metal bioavailability. The uptake of metals by nopal roots correlated with metals in the organic matter and sulfides fraction. Since low levels of humic substances were found in soil collected at cactus roots and because of the low solubility of Pb, Cu and Ag sulfides, the participation of rizosphere processes was suggested in facilitating metal uptake. Metal distribution in PC molecular mass fractions were studied by SEC-ICP-MS and the results compared with the total phytochelatin pool in plants as determined by reversed phase HPLC with spectrofluorimetric detection. The two procedures provide complementary analytical information when the global effect of all metals/metalloids present in soil on PC production is to be studied. Correlation analysis revealed the strong association of Pb with PCs both in roots and in stems, which demonstrates that Pb is important in nopal PCs and suggests that Pb bound to PCs might be transported from roots to stems. For Cu, the correlation between metal-free PCs and metal bound to high molecular mass fraction of plant PC-rich extract was observed only in roots, suggesting differences in the transport of Pb and Cu. In contrast to these metals, no correlation was found for silver, suggesting no association with PCs, even though its elution with a high molecular mass fraction was observed in PC-rich plant extracts. The results obtained from this study indicate the complex role environmental conditions play in the accumulation of heavy metals and in phytochelatin production in the Opuntia genus.

Metals and metal-containing compounds are known to play important roles in many biological processes, including metabolic and detoxification pathways and the formation and function of proteins. Like all organisms, viruses are expected to contain different metals. These metals, either by themselves or in the form of metalloproteins, may be involved in the virus’s ability to infect healthy cells and replicate within them. Identification and speciation of metals in control cells and in cells affected by a virus could be helpful in elucidating infection and replication mechanisms; these might, in turn, be vital to the development of more effective treatments. There has, however, been no extensive investigation of the metals specific viruses contain or affect. The objective of this study was to investigate changes in cellular metal content resulting from herpes simplex virus 1 (HSV-1) infection. Inductively coupled plasma mass spectrometry was used to identify differences between metal concentrations in uninfected and HSV-1-infected mammalian cells. Although it can be assumed that decreases in metal content are a result of cellular response to the virus, increases can be attributed either to cellular response or to the HSV-1 virus itself. Microwave digestion and flow injection methods suitable for small sample volumes were used, and the effects of different virus inactivation procedures were explored. This work is the first step in the identification of metals pertinent to HSV-1 infection and lays the foundation for future studies concentrating on characterization of these metal-associated or containing molecules.

Determination of organophosphorus fire retardants and plasticizers at trace levels in wastewater is described. In this work, microwave assisted extraction (MAE) and solid-phase microextraction (SPME) are used for sample preparation to extract and preconcentrate the analytes, followed by analysis by gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS) for phosphorus-specific detection. Gas chromatography coupled to time of flight mass spectrometry (GC-TOF-MS) was used to confirm the organphosphorus fire retardants in wastewater. The detection limits of organophosphorus fire retardants (OPFRs) were 29 ng L−1 for tri-n-butyl phosphate (TnBP), 45 ng for L−1 for tris(2-butoxyethyl)phosphate (TBEP), and 50 ng L−1 for tris(2-ethylhexyl)phosphate (TEHP). Optimized extraction conditions were performed at 65 °C for 30 min and with 10% NaCl. Application of MAE during the sample preparation prior to the SPME allowed the detection of tris(2-ethylhexyl) phosphate, which has been difficult to determine in previous work. Application of the method to wastewater samples resulted in detecting 3.1 μg L−1 P from TnBP, 5.0 μg L−1 P from TBEP, and 4.0 μg L−1 P from TEHP. The presence of these compounds were also confirmed by SPME-GC-TOF-MS.

Separation and detection of seven V-type (venomous) and G-type (German) organophosphorus nerve agent degradation products by gas chromatography with inductively coupled plasma mass spectrometry (GC–ICPMS) is described. The nonvolatile alkyl phosphonic acid degradation products of interest included ethyl methylphosphonic acid (EMPA, VX acid), isopropyl methylphosphonic acid (IMPA, GB acid), ethyl hydrogen dimethylamidophosphate sodium salt (EDPA, GA acid), isobutyl hydrogen methylphosphonate (IBMPA, RVX acid), as well as pinacolyl methylphosphonic acid (PMPA), methylphosphonic acid (MPA), and cyclohexyl methylphosphonic acid (CMPA, GF acid). N-(tert-Butyldimethylsilyl)-N-methyltrifluroacetamide with 1% TBDMSCl was utilized to form the volatile TBDMS derivatives of the nerve agent degradation products for separation by GC. Exact mass confirmation of the formation of six of the TBDMS derivatives was obtained by GC–time of flight mass spectrometry (TOF-MS). The method developed here allowed for the separation and detection of all seven TBDMS derivatives as well as phosphate in less than ten minutes. Detection limits for the developed method were less than 5 pg with retention times and peak area precisions of less than 0.01 and 6%, respectively. This method was successfully applied to river water and soil matrices. To date this is the first work describing the analysis of chemical warfare agent (CWA) degradation products by GC–ICPMS.

An attempt was made to study selenium (Se) and mercury (Hg) interactions in plants, specifically soybean (Glycine max), by inductively coupled plasma mass spectrometric detection. Greenhouse-cultivated plants were subjected to treatment with different regimens of Se and Hg and analyzed for their metabolized species in roots, stems, leaves, pods and beans. Most of the water-soluble Hg was found to be localized in the roots in association with Se in a high molecular weight entity, as identified by size exclusion chromatography. This entity was also extracted in protein specific isolate, but it resisted enzymatic breakdown. Complete breakdown of this high molecular weight species was accomplished by acid hydrolysis. Optimization of the conditions for acid hydrolysis is discussed. Hg and Se species found in root extract were studied by ion-pairing chromatography. In a sub-study, the Se distribution pattern was found to be unaffected by the presence of Hg, but the amount of Se assimilated was found to be higher in plants coexposed to Hg.

Gas chromatography inductively coupled plasma mass spectrometry (GC-ICPMS) was utilized for the analysis of four organophosphorus nerve agent degradation products in the presence of mixtures of common organophosphorus pesticides. The first degradation products of sarin (isopropyl methylphosphonic acid, GB acid), cyclosarin (cyclohexyl methylphosphonic acid, GF acid), and soman (pinacolyl methylphosphonic acid) as well as their common final hydrolysis product methyl phosphonic acid were utilized throughout these experiments. Due to the non-volatile nature of these alkyl phosphonic acid degradation products, derivatization was performed to generate the volatile tert-butyl dimethylsilyl species. Degraded organophosphorus pesticide standards were obtained for acephate, chlorpyrifos, dichlorvos, ethion, and parathion ethyl. Mixtures consisting of three pesticides in the presence of a single nerve agent degradation product were prepared. GC-ICPMS allowed for the separation and detection of all four degradation products in the presence of pesticide mixtures in just over 12 minutes. This is the first study analyzing pesticides as interfering species for analysis of nerve agent degradation products by GC-ICPMS.

In this study, selenium species from Se containing proteins in mushrooms (Agaricus bisporus and Lentinula edodes) were investigated with size-exclusion liquid chromatography coupled to UV and inductively coupled plasma mass spectrometry (ICP-MS). Different protein extraction protocols were investigated. Variability of the fractionation patterns with three extraction media (0.1 M NaOH, 30 mM Tris–HCl, and enzymatic digestions) was evaluated for both mushroom types. A 24 h Tris–HCl extraction followed by acetone addition was found to be optimal for protein precipitation. Presumably protein bound selenoamino acids were released using enzymes (proteinase K, protease XIV and trypsin). The selenium speciation of the proteolytic extract of the water soluble proteins fraction was carried out by using reversed-phase ion-pairing high performance liquid chromatography (RP-HPIPC) coupled on-line to ICP-MS for selenium specific detection. Selenocystine, selenomethionine, methylselenocysteine and inorganic selenium were established in both samples utilizing retention time standards and standard additions to the sample.

A simple and sensitive method for determination of phosphoric acid triesters at trace levels in human plasma sample is described. In this work, solid-phase microextraction (SPME) is employed as a sample preparation procedure for extraction and pre-concentration of alkyl and aryl phosphates followed by gas chromatography coupled to inductively coupled plasma mass spectrometry (GC–ICP-MS) for phosphorus-specific and very sensitive determination of these compounds in human plasma. The detection limits from blood plasma were 50 ng L−1 (tripropyl phosphate), 17 ng L−1 (tributyl phosphate), 240 ng L−1 (tris(2-chloroethyl) phosphate) and 24 ng L−1 (triphenyl phosphate). Sample preparation involves plasma deproteinization followed by direct immersion SPME with 65 μm poly(dimethylsiloxane/divinylbenzene) fiber. Extraction was performed at 40 °C for 30 min and at pH 7.0 in 10 mM sodium carbonate buffer. The reported method, to our knowledge, describes the first application of SPME with element-specific detection for analysis of phosphoric acid esters. Application of the method to the plasma samples, previously stored in poly(vinyl chloride) plasma bags revealed the presence of triphenyl phosphate, which was further confirmed by SPME GC time-of-flight high-resolution mass spectrometry.

Selenium-containing root exudates were investigated in a known selenium accumulator model plant. Indian mustard (Brassica juncea) plants were grown hydroponically and supplemented with selenite (SeO32−) in a 25% Hoagland's nutrient solution. Additive concentrations were 0, 1, 5 and 20 µg mL−1 Se with five replicate plants per treatment level. Plants were exposed to the respective Se solutions for two weeks, then placed in deionized water for two more weeks. The hydroponic solutions were collected for analysis after the first two weeks of selenium supplementation (day 14) and twice during the deionized water period (days 21 and 28). Separation by ion-pairing high performance liquid chromatography was followed by inductively coupled plasma-mass spectrometry (ICP-MS) for selenium specific detection. Chromatographic peaks unable to be identified by retention-time matching were collected for analysis by electrospray ionization mass spectrometry (ESI-MS). Additional chemical experiments were performed for structural elucidation. Several selenium-containing compounds were identified in the exudate-containing solution and two were identified as selenocystine and the selenosulfate (SSeO32−) ion. The presence of dimethylselenide (CH3SeCH3) is also observed but cannot be attributed exclusively to plant exudation because plants were not grown in sterile conditions. Further, the incorporation of fortified selenoamino acids into peptide structures was found to occur under neutral pH conditions, suggesting that exuded enzymes might facilitate such a reaction. Finally, physiological differences resulting from selenium supplementations were noted and discussed.

The occurrence and form of selenium and mercury were investigated in Indian Mustard, Brassica juncea, a selenium accumulating plant, which had been co-exposed to varying concentration levels of these two elements. Plants were grown and exposed in hydroponic solutions. Following exposure, root exudates were collected in fresh solutions and the head-space around the aerial portions of the plants was sampled. These samples and the harvested plant tissues were then processed for determination of Se and Hg-containing compounds. For the plant tissues, roots, stems and leaves were separated and extracted using a sequential procedure that removed water-soluble species, water-soluble proteins, and dodecyl sulfate-soluble proteins. Size exclusion chromatography allowed further fractionation. High molecular-weight selenium/mercury-containing compounds were found primarily in the plant root extract. Evidence suggests that a Se and Hg complex of high molecular weight may be protein associated. For the analysis of exudate solutions, ion-pairing reversed phase chromatography coupled to ICP-MS was used. Multiple selenium and mercury species were detected, with one mercury-containing compound observed eluting near selenocystine. Plant head-space was sampled with solid phase microextraction and analyzed with GC-ICP-MS and GC-TOFMS. Apart from the primary selenium volatiles and elemental mercury, no volatile species simultaneously containing Se and Hg could be detected.

The separation and analysis of three organophosphorus chemical warfare degradation products is described. Ethyl methylphosphonic acid (EMPA, the major hydrolysis product of VX), isopropyl methylphosphonic acid (IMPA, the major hydrolysis product of Sarin (GB)), and methylphosphonic acid (MPA, the final hydrolysis product of both) were the analytes and were separated by reversed phase ion-pairing high-performance liquid chromatography (RP-IP-HPLC) with the use of myristyl trimethylammonium bromide as ion-pairing reagent and an ammonium acetate–acetic acid buffer system (pH 4.85). An Agilent 7500ce inductively coupled plasma mass spectrometer (ICP-MS) equipped with collision/reaction cell technology was coupled to the chromatographic system for detection of 31P and 47PO+. Historically, ICP-MS detection of phosphorus has been limited due to its high first ionization potential (10.5 eV) and the presence of severe nitrogen polyatomic interferences (such as 14N16O1H+ and 15N16O+) overlapping its only isotope at m/z = 31. Implementation of an octopole reaction cell with helium as the cell gas allowed for removal of the nitrogen polyatomic interferences and reduction of background signal. Detection limits for EMPA, IMPA, and MPA were found to be 263, 183 and 139 pg mL−1, respectively, with separation in less than 15 min. The developed method was successfully applied to the analysis of spiked environmental water and soil samples.

Speciation of iodine in commercially available commonly consumed seaweed samples was performed using a multidimensional chromatographic approach coupled with inductively coupled plasma mass spectrometry (ICP-MS) for element specific detection. Analysis of alkaline extract (0.1 mol l−1 NaOH) by size-exclusion chromatography coupled to ICP-MS (0.03 mol l−1 Tris-HCl, pH 8.0) indicated the association of iodine with both high as well as low molecular weight fractions in Wakame, while in case of Kombu, only low molecular weight iodine species were found. Likely association of iodine with protein as well as polyphenolic species was indicated in the case of Wakame. Anion-exchange chromatography coupled to ICP-MS (0.005 mol l−1 NaOH) confirmed that the most predominant inorganic iodine species present in both type of seaweeds is iodide. Protein bound iodinated species were hydrolyzed by enzymatic digestion using Proteinase K. Analysis of the hydrolysate using reversed-phase HPLC-ICP-MS (0.01 mol l−1 Tris-HCl pH 7.3 ∶ 0.01 mol l−1 Tris-HCl pH 7.3 and 50% MeOH) revealed the presence of monoiodotyrosine and di-iodotyrosine in Wakame, which was later identified by matching the chromatographic retention time with the retention time of commercially available standards.

The present work shows the identification and characterization of Se-methyl selenomethionine (SeMMet) as an important Se species in Brassica juncea roots when grown in the presence of Se-methionine (SeMet) as the Se source. SeMMet was isolated by liquid chromatography employing two different liquid chromatographic mechanisms: reversed-phase ion-pairing using heptafluorobutyric acid as counter ion and cation exchange using a pyridinium formate gradient (pH 3). Inductively coupled plasma mass spectrometry was used for the detection of Se. SeMMet was characterized by electrospray quadrupole time-of-flight MS in both a synthesized standard and in the roots extract using collision-induced dissociation of the selected ion. Preliminary evidence suggests that Brassica juncea may also produce dimethylselenonium propionate, although to a much lesser extent.

High-performance chelation ion chromatography (HPCIC) was employed to retain cationic Cr(III) on an anion-exchange column and hence allow the separation of the two most prevalent forms of chromium, Cr(III) and Cr(VI). A mobile phase of nitric acid was utilized at pH = 1.5; additionally, 2,6-pyridinedicarboxylic acid was used at a concentration of 6 mM. Additives with different structural characteristics were used in an effort to elucidate retention mechanisms. Inductively-coupled plasma mass spectrometry was used for chromium detection. A collision cell was utilized to reduce chloride-based polyatomic ions that may interfere with the detection of Cr(III), and a detection limit study yielded levels in the low part-per-billion range. The newly developed method was applied to the chromatographic analysis of samples of an incubation medium containing Cr(VI) incubated with cell nuclei.

In this study speciation of selenium in selenium-enriched green onions (Allium fistulosum) was done with reversed-phase ion-pairing high performance liquid chromatography (RP-IP-HPLC) and size-exclusion chromatography (SEC) coupled on-line to ICP-MS for selenium specific detection. The plant extract obtained using sodium hydroxide (0.1 mol l−1) analyzed by SEC (CAPS 10 mmol l−1, pH 10.0) with ICP-MS detection showed the incorporation of selenium in both high (∼12 kDa) and low molecular weight (0.36–2 kDa) fractions. Presumably protein bound selenoamino acids were released using enzymes (Proteinase K and Protease XIV) and selenoamino acids found in cytosol in their free form were extracted using 0.1 M HCl. The extracts were analyzed for speciation studies by RP-IP-HPLC [0.1% (v/v) heptafluorobutyric acid, 5% (v/v) methanol, pH 2.5]. Matching the chromatographic retention times with commercially available standards provided evidence for the presence of Se-cystine, methylselenocysteine, Se-methionine, and inorganic selenium. Electrospray ionization ion trap mass spectrometry (ESI-ITMS) confirmed the presence of γ-glutamyl-Se-methylselenocysteine in green onions as has been reported in other onion types.

A new analytical methodology using high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) was applied to study the presence of possible degradation products in levothyroxine tablets. The analytical methodology takes advantage of the element-specific and highly-sensitive I detection provided by ICP-MS and is applied to the speciation of: 3,3′,5,5′-tetraiodothyronine (T4); 3,3′,5-triiodothyronine (T3); 3,5-diiodothyronine (T2); 3,3′,5,5′-tetraiodothyroacetic acid (TTAA4); 3,3′,5-triiodothyroacetic acid (TTAA3); and 3,5-diiodothyroacetic acid (TTAA2). Chromatographic conditions were optimized by using UV absorption at 225 nm and ICP-MS detection of 127I. Complete chromatographic resolution of the levothyroxine degradation products within 25 min was obtained using 22% (v/v) acetonitrile at pH 2.3, adjusted with 0.08% (v/v) trifluoroacetic acid. The introduction of the mobile phase containing acetonitrile was performed by post column on-line dilution (1∶3.3) of the chromatographic eluent with a 2% (v/v) nitric acid solution using a PTFE tee. The separations with either detector were good with little detector effect on the resolution. The peak broadening caused by on-line dilution was insignificant. The detection limits obtained with UV detection ranged from 28.9 to 34.5 µg l−1, whereas those obtained with the plasma detector were about 175–375 times better (lower). Finally, the analytical methodology was applied to the determination of possible iodine species originated by degradation of T4 in synthetic and commercial levothyroxine sodium tablets.

An analytical method using high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) was developed for the separation and determination of iodophenol compounds in human urine samples. The advantages of using highly-sensitive 127I detection provided by ICP-MS for the speciation of 2,4,6-triiodophenol, 4-iodophenol and 2-iodophenol are shown in this work. 2,4,6-triiodophenol is also referred to as Bobel-24, an anti-inflammatory. Chromatographic conditions were optimized using UV absorption at 254 nm and ICP-MS detection of 127I and a comparative study between these two detection systems was developed. The separation of iodophenol species was studied by two different chromatographic modes: reversed-phase and anion-exchange chromatography. Complete chromatographic resolution of the iodophenol species was obtained in 100% aqueous phase solution using gradient elution of NaOH (50 mmol l−1) and NaOH (50 mmol l−1) with hexadecyltrimethylammonium bromide (CTAB). Total resolution was obtained in a minimal retention time of 7 min. Since the separation of the iodophenol species was performed in an aqueous mobile phase, high sensitivity was obtained with the ICP-MS instrument. The detection limits obtained were between 0.08–0.22 µg l−1 as iodophenol compounds. On the other hand, the detection limits obtained with UV detection were 300–325 times higher with ICP-MS. Finally, the analytical methodology was applied for the determination of iodophenols in human urine.

In this review, a full discussion and update of the state-of-the-art of gas chromatography (GC) coupled to all known plasma spectrometers is presented. A brief introductive discussion of the advantages and disadvantages of GC–plasma interfaces, as well as types of plasmas and mass spectrometers, is given. The plasma-based techniques covered include inductively coupled plasma mass spectrometry (ICP-MS) microwave-induced plasma optical emission spectrometry (MIP-OES), and inductively coupled plasma optical emission spectrometry (ICP-OES). Also, different variants of plasma sources, such as low power plasmas and glow discharge (GD) sources, are described and compared with respect to their capabilities in elemental speciation. Recent advances and alternative mass analyzers (collision/reaction cell; time-of-flight; double-focusing sector field) are also mentioned. Different aspects of the GC–plasma coupling are discussed with particular attention to the applications of these hyphenated techniques to the analysis of elemental species. Additionally, classical and modern sample preparation methods, including extraction and/or preconcentration and derivatization reactions, are presented and evaluated.

An analytical methodology using gas chromatography (GC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) was applied in order to analyze iodophenols. The new method takes advantage of the element-specific and highly-sensitive detection provided by the ICP-MS technique and is applied to the analysis of 2-iodophenol, 4-iodophenol and 2,4,6-triiodophenol. The determination of these iodophenols at low ng l−1 levels was possible by optimizing and applying solid-phase microextraction (SPME). Diverse types of SPME fibers, including the 100 µm poly(dimethylsiloxane) (100-PDMS), 7 µm poly(dimethylsiloxane) (7-PDMS), 75 µm Carboxen-poly(dimethylsiloxane) (CAR-PDMS) and 85 µm polyacrylate, were studied and the CAR-PDMS coated fiber was found to work best with the iodinated compounds of interest. Optimal conditions for the extraction and preconcentration of the iodophenols from water samples were found to be at pH = 2, an extraction time of 30 min and desorption in the GC injector at 290 °C for 2 min. Additionally, a new commercially available interface between GC and ICP-MS was used by heating the entire device at 325 °C in order to maintain peak sharpness. The introduction of oxygen as an optional gas provided an increase in sensitivity; instrument detection limits within the low ng l−1 level are demonstrated for all species examined. The precision, as relative standard deviation, did not exceed 5.4% for 10 manual injections. The method was applied to the speciation analysis of iodophenols in river, tap, and bottled water samples.

Organophosphorus pesticides (OP) are used widely in agricultural and residential applications as insecticides, herbicides and fungicides. This family of chemicals is one that replaced the organochlorine pesticides banned for use in the United States in the 1970s. In this work, inductively coupled plasma mass spectrometry (ICP-MS) is explored as an option for the detection of OPs, monitoring the phosphorus present in the compounds previously separated by GC. Historically, phosphorus has been recognized as one of the elements that is difficult to analyze in an argon plasma. This is due to its relatively high ionization potential (10.5 eV) as well as the inherent presence of the polyatomic interferences 14N16O1H+ and 15N16O+, overlapping its only isotope at m/z = 31. In this work, the use of a commercially available GC-ICP-MS interface, in conjunction with the addition of small amounts of optional gases, has been investigated to obtain enhanced sensitivity and it is found that nitrogen yields an increase in sensitivity of over one order of magnitude. Accompanying this increase in sensitivity is an observed increase in the background due to the above detailed interferences formed in the gas phase. A collision cell is employed to reduce this background without affecting analyte signal using He as collision gas. Instrument detection limits in the high ng L−1 range are reported and the developed methodology is applied to the analysis of tap water samples from the City of Cincinnati.

Solid-phase microextraction (SPME) is used as a sample preparation strategy for gas chromatographic (GC) analysis of the seleno amino acids, selenomethionine (SeMet), selenoethionine (SeEt) and selenocystine (SeCys). Acylation of the amino group and esterification of the carboxylic group in these compounds was performed with isobutylchloroformate to increase volatility. The amino acid derivatives were then extracted by silica fibers with polydimethylsiloxane (PDMS) coatings prepared by the sol–gel process. Investigations of extraction time, acid and salt addition, and polymer length (for the sol–gel process) were conducted with the goal of procedural optimization. Initial characterizations were conducted using gas chromatography with flame ionization detection (GC-FID). Inductively coupled plasma mass spectrometric detection was employed for final selenium detection. Sub-ppb detection limits were obtained for all analytes although relative standard deviations were higher than those typically obtained in solid-phase microextraction.

A variety of extraction procedures were evaluated for the extraction of arsenic and other analytes from lobster tissue samples using inductively coupled plasma mass spectrometry (ICP-MS) detection. Soxhlet, room temperature mixing, sonication, microwave assisted, supercritical carbon dioxide and subcritical water extractions were evaluated for a variety of solvent systems and optimum conditions determined using a partially defatted Lobster Hepatopancreas marine certified reference material, TORT-2 (National Research Council of Canada). The solubility trends and solvents into which the analytes extracted gave an indication as to the polar/non-polar nature of the compounds present. Analytes that prefer water are probably more polar or inorganic, while those preferring methanol solutions are less polar or organic in nature. Arsenic, cadmium, cobalt, molybdenum and selenium were probably all present in TORT-2 in both polar inorganic and non-polar organic forms. While TORT-2 may have contained similar amounts of selenium in both forms, the results suggested that more of the arsenic was present as less polar or more organic compounds, and cobalt existed mainly as more polar or inorganic species. Most of the extraction techniques suggested that, although there may be some less polar organic forms present, more of the cadmium was probably present as polar inorganic compounds. Additionally, most techniques indicated that molybdenum was possibly all less polar or more organic in nature. In general, microwave assisted extraction (MAE) yielded comparable or improved recoveries for all of the analytes monitored and usually required less solvent. Additionally, MAE proved to be the mildest, fastest, least complicated and most reproducible extraction technique evaluated. MAE at 75 °C for 2 min exposure time yielded quantitative recovery of arsenic from TORT-2. These conditions were evaluated for lobster tissue samples purchased from a local restaurant. Separate evaluation of the lobster meat and organs resulted in quantitative recoveries of arsenic from both tissue samples. The results indicated that the extraction efficiencies might have some dependence upon the extraction technique, extraction conditions, analyte, solvent, and sample matrix.

The term brominated flame retardants (BFRs) refers to a class of compounds added during the manufacturing of some plastics to impede or even suppress the combustion process by depriving the flames of oxygen. Polybrominated diphenyl ethers (PBDEs) represent a group of compounds used in this capacity, and as a result of product emission/disposal, these structures have been found in both the environment and biota. In this work, inductively coupled plasma mass spectrometry (ICP-MS) coupled to gas chromatography (GC), in the form of fast gas chromatography, is explored as an option to shorten analysis times for the PBDEs with this element-specific detector; a run time of 10 min was ultimately established. The use of a new commercially available interface has been accomplished that has the requirement of heating the entire device at 325 °C in order to maintain the resolution between the species previously separated. The introduction of helium as an optional gas provides an increase in sensitivity; instrument detection limits within the low ppb level are demonstrated for all species examined. The precision, as relative standard deviation, does not exceed 7% for 5 manual injections. More rigorous control of the interface temperature seems to be required for analyzing the species with more than six bromine atoms per molecule. The method is applied to the analysis of sewage sludge samples obtained from the Metropolitan Sewer District of Greater Cincinnati and the presence of three of the most abundant PBDEs has been observed (BDE-47, BDE-99 and BDE-100).

Various plants can accumulate Se up to the thousands of ppm. These are called accumulators and they have potential to remediate areas contaminated with this metalloid. Some of them, like Arabidopsis thaliana or Brassica juncea (Indian mustard) have been investigated in terms of the Se metabolic pathway. To date few studies have been done for selenium speciation with most studies reporting total selenium concentration in various parts of the plant. This present report summarizes some of the studies carried out in terms of: extraction of Se species, cleaning procedures, separation methodologies and mass spectrometric techniques employed. The use of inductively coupled plasma mass spectrometry (ICP-MS) in conjunction with liquid or gas chromatographic techniques (HPLC and GC) as separation techniques provide an attractive methodology for determining Se species in plants. Some of the species produced by the plant, such as Se-methylselenocysteine or Se-methylselenomethionine can be identified at ppb levels by RP-HPLC-ICP-MS, while others needed to be further characterized by ES-MS. The coupling of GC-ICP-MS using solid phase microextraction (SPME) as sample preparation system is also evaluated for the determination of the Se/S volatile species in the head-space of Brassica juncea seedlings. Detection limits on the ppt level (7–300 ppt depending on the species) and adequate precision for Se and S species suggest GC-ICP-MS as an excellent methodology for determination of volatiles with minimum sample preparation.

The chiral speciation of DL-selenomethionine by capillary electrophoresis (CE) with UV absorbance and inductively coupled plasma mass spectrometry (ICP-MS) is described. Chiral derivatization of DL-selenomethionine with 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide (Marfey's reagent) forms diastereomers that are separated with CE in reversed polarity. Three CE buffer systems were evaluated using UV absorbance detection. A 30 mM ammonium phosphate buffer at pH 3.3 was chosen for good resolution of the D- and L-forms in under 14 min. Limits of detection for D- and L-selenomethionine were 250 ppb (ng mL−1) using CE-UV, and 50 ppb using CE-ICP-MS. The migration time reproducibility of both detection limits was comparable (∼2%). This method was applied to the qualitative chiral identification of selenomethionine in selenized yeast digested with proteinase K (enzymatic hydrolysis).

In this work, the speciation of elements in compost was studied with emphasis on their binding to humic substances. In order to assess the distribution of As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, U, Th and Zn among molecular weight fractions of humic substances, the compost extract (extracted by 0.1 mol l−1 sodium pyrophosphate) was analyzed by size exclusion chromatography coupled on-line with UV–Vis spectrophotometric and ICP-MS detection. Similar chromatograms were obtained for standard humic acid (Fluka) and for compost extract (254 nm, 400 nm) and three size fractions were operationally defined that corresponded to the apparent molecular weight ranges >15 kDa, 1–15 kDa and <1 kDa. The percentage of total element content in compost that was leached to the extract ranged from 30% up to 100% for different elements. The elution profiles of Co, Cr, Cu, Ni and Pb (ICP-MS) followed that of humic substances, while for other elements the bulk elution peak matched the retention time observed for the element in the absence of compost extract. Spiking experiments were carried out to confirm elements' binding and to estimate the affinity of individual elements for humic substances derived from compost. The results obtained indicated the following order of decreasing affinity: Cu > Ni > Co > Pb > Cd > (Cr, U, Th) ≫ (As, Mn, Mo, Zn). After standard addition, further binding of Cu, Ni and Co with the two molecular weight fractions of humic substances was observed, indicating that humic substances derived from compost were not saturated with these elements.

A gradient anion exchange chromatographic technique was developed for the separation of arsenobetaine (AsB), arsenocholine (AsC), arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) in one chromatographic run. This technique used low residue ammonium carbonate buffer and the inductively coupled plasma-mass spectrometry (ICP-MS) chromatograms showed little baseline drift. Gradient elution improved peak shape and peak separation. The separation was completed in approximately 27 min with low detection limits (0.017–0.029 μg As kg−1). Baseline resolution of all the arsenic species evaluated was achieved when the concentration of AsC was less than approximately 12.5 μg As kg−1. This technique was successfully applied to different extracts of a standard reference material, TORT-2, and lobster tissue. AsB was found to be the major arsenic species present. AsC, DMAA, MMAA and AsV were also found, although MMAA was not detected in all of the TORT-2 extracts. Two unknown peaks found may be due to the presence of arsenosugars or other arsenic species. Discrepancy between extraction recoveries previously determined using flow injection–ICP-MS and the high-performance liquid chromatography–ICP-MS was observed in some cases. The differences may be due to the extraction technique and/or conditions at which the extractions were performed.

In this study, a rapid and sensitive high performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC–ICP–MS) determination of primary As species in fish tissues and urine is reported. The separation was achieved on an Altima C18 column with a mobile phase containing citric acid and hexanesulfonic acid (pH 4.5). As(V), monomethylarsonic acid (MMA), As(III), dimethylarsinic acid (DMA) and arsenobetaine (AsB) were separated in less than 4 min with retention times of 83, 99, 130, 166 and 208 s, respectively. This separation of five species in less than 4 min should be attractive to those interested in As speciation. The quantification limits were 44, 56, 94, 64, 66 ng l−1 and the relative standard deviations (R.S.D.) for day-to-day injections of As at 2 μg l−1 were 2.0, 3.1, 2.4, 3.8 and 4.0%. The procedure was tested using two reference materials (DORM-2 dogfish muscle tissue, NIST SRM 2670 Freeze-dried Urine, normal level) and then applied to real-world samples. The results obtained demonstrate the suitability of the procedure for screening and quantification at physiological levels of primary As species in biological samples.

A radiofrequency glow discharge (rf-GD) has been used as an ion source for mass spectrometry using gas chromatography as the sample introduction technique for the speciation of seleno amino acids. The use of helium as the plasma gas allowed the monitoring of selenium's major isotope (80Se), interfered by polyatomic species when using Ar as the plasma gas. Optimization of the power and pressure of the source was undertaken to achieve the best sensitivity for selenium determination and detection limits of about 100 pg (as Se) have been obtained for the derivatized Se-methionine. Studying the cell pressure and power on the fragmentation patterns obtained for Se-methionine and Se-ethionine has also been undertaken to characterize the source. No significant variations were observed on the mass spectra under different operating conditions, although noticeable variation of the fragment intensities was observed. The system has been applied to the determination of Se-methionine in selenium-enriched yeast after enzymatic extraction of the corresponding species using Proteinase K to cleave the peptide bonds. The results obtained showed a Se-methionine content of about 78% in the enriched yeast.

Significant effort has been devoted to studying the mutually protective effect of selenium and mercury in mammals. However, a limited number of studies have investigated the potential selenium–mercury antagonism in plants, which may prove informative for ultimate phytoremediation purposes. In this study, the Allium fistulosum, green onion, was used to investigate the metabolic fate of mercury in conjunction with or exclusion of selenium. The plants were grown in perlite media and supplemented with sodium selenite and mercuric chloride. Total elemental analysisviamicrowave digestion and inductively coupled plasma mass spectrometry (ICPMS) detection, showed that the A. fistulosum accumulated 50 times more mercury than selenium, both elements were predominately sequestered in the root fraction, and a mutual antagonism was observed. Size exclusion and capillary reversed phase chromatography were coupled to ICPMS to investigate the plant root and leaf extracts. The data suggest a possible selenium–mercury association in a protein containing macromolecule, which is not further metabolized upon translocation to the aerial plant regions. The selenium–mercury association may be formed by combining small selenium molecules, which are normally translocated to the aerial plant regions. Data from enzymatic and acid hydrolysis suggests formation of stable mercury metabolites in the plant when supplemented in conjunction with selenium.

Determination of organophosphorus fire retardants and plasticizers at trace levels in wastewater is described. In this work, microwave assisted extraction (MAE) and solid-phase microextraction (SPME) are used for sample preparation to extract and preconcentrate the analytes, followed by analysis by gas chromatography coupled to inductively coupled plasma mass spectrometry (GC-ICP-MS) for phosphorus-specific detection. Gas chromatography coupled to time of flight mass spectrometry (GC-TOF-MS) was used to confirm the organphosphorus fire retardants in wastewater. The detection limits of organophosphorus fire retardants (OPFRs) were 29 ng L−1 for tri-n-butyl phosphate (TnBP), 45 ng for L−1 for tris(2-butoxyethyl)phosphate (TBEP), and 50 ng L−1 for tris(2-ethylhexyl)phosphate (TEHP). Optimized extraction conditions were performed at 65 °C for 30 min and with 10% NaCl. Application of MAE during the sample preparation prior to the SPME allowed the detection of tris(2-ethylhexyl) phosphate, which has been difficult to determine in previous work. Application of the method to wastewater samples resulted in detecting 3.1 μg L−1 P from TnBP, 5.0 μg L−1 P from TBEP, and 4.0 μg L−1 P from TEHP. The presence of these compounds were also confirmed by SPME-GC-TOF-MS.

Se-enriched rice was prepared by foliar fertilization. In the present work, speciation and distribution of Se in Se-enriched rice and non-supplemented rice was evaluated by ion-paring reversed phase (IP-RP) and strong anion-exchange (SAX) chromatography coupled with inductively coupled plasma mass spectrometry (ICPMS) detection. Three extraction procedures: water extraction, acid extraction (0.1 M HCl) and enzymatic hydrolysis were studied with a combination of protease XIV and amylase with ultrasonic bath and the latter was found to be optimal for the extraction of selenospecies. The chromatograms obtained revealed that the major selenospecies found in Se-enriched rice was selenomethionine (SeMet), which was further identified by nanoelectrospray ionization, ion trap mass spectrometry (nano-ESI-ITMS). Approximately 86.9% of the total Se in the Se-enriched rice extract was SeMet, while only 26.7% of non-supplemented rice extract was due to SeMet. Moreover, nearly 60% of inorganic Se in the form of SeIV was present in the non-supplemented rice, while only 6.8% of inorganic Se as SeIV and SeVI was found in Se-enriched rice extract with minor selenocystine (SeCys2) and trace selenomethionine selenoxide (SeOMet) present. The results proved that SeMet was efficiently extracted by the enzymatic hydrolysis without oxidization. The high SeMet concentrations of Se-enriched rice indicate a high inorganic to organic conversion when Se enrichment was carried out by foliar application. Since SeMet is a readily bioavailable Se species for animals, Se-enriched rice could be considered for supplementation in Se poor geographical regions.

This work focuses on phytochelatins (PCs) in plants chronically exposed to low or moderate metal concentrations in soil, which commonly occurs in natural environments. The original approach was to evaluate PCs in nopal (Opuntia ficus) in relation to the plant and soil levels of Cd, Pb, Cu and Ag. These four metals were selected because of their known capability to induce PCs in plants and also because of their abundance in the region of Guanajuato (Mexico), where the nopal plants were collected. ICP-MS determination of metals in nopal roots, stems and in soil fractions provided information relevant to their bioavailability in soil as well as their uptake by nopal. In search of a possible relationship between the parameters measured, correlation analysis was carried out (Cd was not considered owing to its low levels found in the plant tissues). The results obtained indicate that sequential metal leaching from soil does not always provide direct information on metal bioavailability. The uptake of metals by nopal roots correlated with metals in the organic matter and sulfides fraction. Since low levels of humic substances were found in soil collected at cactus roots and because of the low solubility of Pb, Cu and Ag sulfides, the participation of rizosphere processes was suggested in facilitating metal uptake. Metal distribution in PC molecular mass fractions were studied by SEC-ICP-MS and the results compared with the total phytochelatin pool in plants as determined by reversed phase HPLC with spectrofluorimetric detection. The two procedures provide complementary analytical information when the global effect of all metals/metalloids present in soil on PC production is to be studied. Correlation analysis revealed the strong association of Pb with PCs both in roots and in stems, which demonstrates that Pb is important in nopal PCs and suggests that Pb bound to PCs might be transported from roots to stems. For Cu, the correlation between metal-free PCs and metal bound to high molecular mass fraction of plant PC-rich extract was observed only in roots, suggesting differences in the transport of Pb and Cu. In contrast to these metals, no correlation was found for silver, suggesting no association with PCs, even though its elution with a high molecular mass fraction was observed in PC-rich plant extracts. The results obtained from this study indicate the complex role environmental conditions play in the accumulation of heavy metals and in phytochelatin production in the Opuntia genus.

The use of water pipes or hookahs to smoke tobacco formulations has gained great popularity among young people around the world, but the potential health hazards have not yet been adequately evaluated. The complexity of a multi component hookah apparatus, compared with cigarettes and cigars, makes it difficult to study under laboratory conditions. For this reason the detailed study of its components simplify the task. In this study the charcoal, which is traditionally used as the heat source, was analyzed for metal content before and after combustion. Sixteen different hookah charcoals were analyzed representing different compositions and manufacturing processes as well as different geographic origins. ICP-MS was used to measure 24 elements: Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th, U. The total concentration ranges of toxic elements in native (un-burned) charcoals were: arsenic 14.8–10300 ng g−1, cadmium 3.3–2100 ng g−1, and lead 95.2–55600 ng g−1. The mass-loss-corrected content of elements in combusted charcoals shows that most of the metals remain in the ash, with iron, cadmium and lead as exceptions. Because of the high content of arsenic in some samples an extraction and speciation method was developed to quantify four chemical forms of arsenic. Nitric acid, and phosphoric acid were evaluated as extractants used in a heating block, and ascorbic acid was used to minimize oxidation of inorganic As3+ to As5+. Anion exchange chromatography coupled to ICP-MS was used to carry out the separation and quantification of arsenic species. The best conditions in terms of extraction efficiencies and species conservation were 1.2 mol L−1 H3PO4, with 0.2 mol L−1 ascorbic acid. As5+ was the dominant arsenic species in charcoal. Concentrations ranged from 0.08–2.42 mg kg−1, for As3+ and 0.46–8.36 mg kg−1 for As5+. The results show high variation depending on the sample origin and composition. The possibility of volatile cadmium and lead contributions to the primary and second hand smoke by the charcoal are suggested and the high levels of arsenic suggest that for certain charcoals there may be more hazard from them than from the tobacco formulation.

The objective of this review is to note recent novel developments and applications rather than to be comprehensive. We intend to explore instrumental advances that demonstrate enhanced analytical capability. Along these same lines, there have been a number of recent papers coupling solid phase microextraction with GC-ICPMS and these will be discussed. Not only does this preparation technique present several advantages, such as environmental friendliness through reduced solvent consumption, it also lends itself to easy incorporation into a GC analytical scheme. Finally, new explorations in the analysis of the traditional metal species, as well as novel applications of species of nontraditional elements, are presented.

Kale (Brassica oleracea A.) can accumulate high concentrations of Se, as well as lutein and β-carotene, which have important human health benefits and possess strong antioxidant properties. In the present study, kale plants were cultivated in soil supplemented with sodium selenite or sodium selenate. The plants accumulated over 20 times higher concentration of selenium in the selenate-enriched soil compared with selenite-enriched soil. Selenium accumulation did not suppress the plant's uptake of the essential metals, Fe, Cu and Zn. Speciation of selenium in the plant was performed via size-exclusion chromatography and ion-pairing reversed phase chromatography using inductively coupled plasma mass spectrometry (ICPMS) and nano-electrospray ion trap mass spectrometry (nanoESI-ITMS) for detection. In ion-pairing reversed phase chromatography, 0.02% HFBA was found to facilitate separating the selenium metabolites without hampering ESI-ITMS ionization. MS2/MS3 spectra were successfully obtained for identification of Se-methylselenocysteine (MeSeCys). MeSeCys was the prominent selenium metabolite formed in kale, which has been suggested as a chemopreventive food supplement. The Se species in leaf are significantly different from those in stem. The leaf shows higher content of high molecular weight selenium than the stem, while the stem produced higher amounts of MeSeCys than the leaf, indicating the metabolism to MeSeCys competes with the production of high molecular weight selenium forms. The plant leaf, when supplemented with Se(IV), contained the highest amount of high molecular weight selenium (49%) as well as the lowest amount of MeSeCys (4%).

Developing a reliable and robust trace level method for organophosphates in the presence of relatively high inorganic phosphate is an area of interest for further method development. Since the advent of collision/reaction cell technology, inductively coupled plasma mass spectrometry (ICPMS) has been used with a variety of sample types for elemental phosphorus detection at m/z = 31. However, with many samples inorganic phosphate may be orders of magnitude higher than organophosphates, presenting a major interference to quantification. Therefore, removal of inorganic phosphate to levels low enough to minimize the interference would prove beneficial for more effective organophosphate analyses. In this study, applicable to most organophosphate containing samples, the illustration is to nerve agent degradation products as they might contaminate food and environmental systems after their initial formation. Calcium chloride was chosen as a coagulant mix and ammonium hydroxide was chosen to adjust the pH in order to remove inorganic phosphate at the sample preparation step. High performance liquid chromatography (HPLC) coupled with ICPMS was utilized for analysis. The results show that inorganic phosphate, at concentrations as high as 10000 µg mL−1, can be sufficiently removed by precipitation with calcium at pH > 9 while the organophosphorus chemical warfare agent degradation products, CWADPs, remain intact. Applications to apple juice and cola drink indicate that this method is suitable for more complex matrices containing relatively high levels of inorganic phosphate.