Co-reporter:Qingxiang Zhou, Man Lei, Yongli Liu, Yalin Wu, Yongyong Yuan
Talanta 2017 Volume 175(Volume 175) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.talanta.2017.07.043
•Functional core-shell magnetic nano-material Fe@Ag@DMB was firstly synthesised.•Fe@Ag@DMB exhibited excellent enrichment for Pb2+, Cd2+, and Hg2+.•Developed MSPE method was simple, rapid, sensitive, easy to operate and separation.•Developed method provided high sensitivity.Pollution resulted from heavy metal ions have absorbed much attention, and it is of great importance to develop sensitive and simultaneous determination method for them with common technologies without highly sensitive instruments. We prepared a new and functional core-shell magnetic nano-material, Fe@Ag@dimercaptobenzene (Fe@Ag@DMB), by a one-step method with sodium borohydride as the reducing agent and transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) were used for characterisation. The mercapto functional groups on the newly synthesised magnetic nanoparticles could interact with Cd2+, Pb2+, and Hg2+ ions in water samples and then efficient extraction for Cd2+, Pb2+, and Hg2+ ions was achieved. DDTC-Na solution was a good elutent for elution of these ions from Fe@Ag@DMB nanoparticles. Based on these, a sensitive method was developed for simultaneous preconcentration and determination of the aforementioned ions using magnetic Fe@Ag@DMB nanoparticles as the magnetic solid phase extraction adsorbent prior to high performance liquid chromatography coupled with variable wavelength detection. Under the optimal conditions, the detection limits of the three metal ions were in the range of 0.011–0.031 μg L−1, and precisions were below 2.37% (n=6). The proposed method was evaluated with real water samples, and excellent spiked recoveries achieved indicated that the developed method would be a promising tool for monitoring these heavy metal ions in water samples.Download high-res image (124KB)Download full-size image
Co-reporter:Qingxiang Zhou, Man Lei, Jing Li, Kuifu Zhao, Yongli Liu
Separation and Purification Technology 2017 Volume 182(Volume 182) pp:
Publication Date(Web):12 July 2017
DOI:10.1016/j.seppur.2017.01.071
•Fe@MgAl-layered double hydroxide was firstly synthesized by co-precipitation.•Fe@MgAl LDH exhibited excellent adsorption for BPA, 4-NP and 4-OP.•Developed method was simple, rapid, sensitive, easy to operate and separation.Mg-Al-layered double hydroxide (Mg-Al-LDH) modified nanoscale zero-valent iron (NZVI) (Fe@MgAl-LDH) was firstly synthesized and characterized by several techniques. The results showed that the layered double hydroxides were coated on the surface of nanoscale zero-valent iron particles. This new material exhibited good adsorption for bisphenol A, 4-octylphenol and 4-nonylphenol from water samples. Based on these, a sensitive method was developed for the extraction and preconcentration of bisphenol A, 4-octylphenol and 4-nonylphenol using magnetic Fe@MgAl-LDH nanoparticles as the solid phase extraction adsorbents prior to high performance liquid chromatography coupled with variable wavelength detection. Under the optimal conditions, linear responses were achieved in the range of 0.5–200 μg L−1 with the correlation coefficients (r) above 0.999. The detection limits of three analytes were in the range of 0.24–0.34 μg L−1, and precisions were all below 2.5% (n = 6). The proposed method was evaluated with real water samples and the excellent spiked recoveries in the range of 96.0–99.3% were achieved.
Co-reporter:Qingxiang Zhou;Man Lei;Jing Li;Yongli Liu;Kuifu Zhao;Danchen Zhao
Microchimica Acta 2017 Volume 184( Issue 4) pp:1029-1036
Publication Date(Web):2017/04/01
DOI:10.1007/s00604-017-2094-6
Metal organic frameworks of type MOF-5 exhibit good adsorption capacity for many organic compounds. The authors have used nanoscale silica-coated zerovalent iron and MOF-5 to prepare, by co-precipitation, a novel magnetic nanomaterial of type Fe@MOF-5. Its morphology and structure were characterized by transmission electron microscopy and X-ray diffraction. The nanomaterial is shown to be well suited for magnetic solid phase extraction for five kinds of N- and S-containing polycyclic aromatic hydrocarbons prior to quantitation by HPLC. The limits of detection are in the 25 to 33 ng⋅L−1 concentration range. Four real water samples were used to validate the method, and the recoveries of spiked samples with concentrations of 5 and 10 ppb were found to be in the range between 92.6 and 97.3% (n = 3). The Fe@MOF-5 sorbent obviously has excellent adsorption capability for such compounds, can be fairly easily synthesized, displays sensitivity, simplicity, ease of operation, and can be prepared at low costs. In our perception, it has a large potential in terms of monitoring such environmental pollutants.
Co-reporter:Qingxiang Zhou, Man Lei, Yalin Wu, Yongyong Yuan
Journal of Chromatography A 2017 Volume 1487(Volume 1487) pp:
Publication Date(Web):3 March 2017
DOI:10.1016/j.chroma.2017.01.046
•Fe@MIL-101 was firstly synthesized by co-precipitation.•Fe@MIL-101 exhibited high enrichment for typical PAHs.•The advantages included high sensitivity, easy synthesis, separation and operation.Metal-organic framework material has been paid more attention because of its good physical and chemical properties. Nanoscale zero valent iron is also in the center of concern recently. Combination of their merits will give impressive results. Present study firstly synthesized a new magnetic nanomaterial nano-scale zero valent iron-functionalized metal-organic framworks MIL-101 (Fe@MIL-101) by co-precipitation method. The morphology and structure of the as-prepared Fe@MIL-101 were characterized by transmission electron microscopy and X-ray diffraction, etc. The experimental results showed that Fe@MIL-101 earned good adsorption ability to polycyclic aromatic hydrocarbons. The limits of detection of developed magnetic solid phase extraction were all below 0.064 μg L−1 and precision can be expressed as relative standard deviation (RSD, %) and which was better than 4.4% (n = 6). The real water analysis indicated that the spiked recoveries were satisfied, and Fe@MIL-101 earned excellent reusability. All these demonstrated that Fe@MIL-101 exhibited excellent adsorption capability to polycyclic aromatic hydrocarbons and would be a good adsorbent for development of new monitoring methods for environmental pollutants.
Co-reporter:Qingxiang Zhou, An Xing, Jing Li, Danchen Zhao, Kuifu Zhao, Man Lei
Electrochimica Acta 2016 Volume 209() pp:379-388
Publication Date(Web):10 August 2016
DOI:10.1016/j.electacta.2016.05.094
Present study described a high performance and rapid degradation technique for bisphenol A under simulated solar light irradiation by photoelectrocatalytic degradation with CeO2 and reduced graphene oxide co-modified TiO2 nanotube arrays (RGO-CeO2-TNAs) in combination with Fenton reaction. In the photoelectrocatalytic system (PEC), CeO2 and reduced graphene oxide co-modification significantly improved the degradation efficiency due to the synergistic effect of them. With the introduction of Fenton reaction, the expected further effective enhancement of degradation efficiency was achieved. Under the optimal condition, the degradation of BPA reached a high reaction rate constant of 0.0146 min−1. In comparison, photoelectrocatalytic process exhibited higher degradation efficiency than that of photocatalytic-Fenton (PC-Fenton), electrocatalytic-Fenton (EC-Fenton) and Fenton processes. The stability and reusability of RGO-CeO2-TNAs was investigated and the results demonstrated that rarely decline of degradation efficiency was achieved and the degradation efficiencies of the repeated degradation experiments were all over 80% for ten runs. All these indicated that there was markedly synergistic enhancement effect between Fenton reaction and PEC process using RGO-CeO2-TNAs as the photoelectrode for degradation of bisphenol A. All these results indicated thatpresent method provided a potential powerful tool for the control and removal of bisphenol A and other pollutants in the future.
Co-reporter:Qingxiang Zhou, Man Lei, Jing Li, Kuifu Zhao, Yongli Liu
Journal of Chromatography A 2016 Volume 1441() pp:1-7
Publication Date(Web):8 April 2016
DOI:10.1016/j.chroma.2016.02.061
•Fe@MgAl-layered double hydroxide was firstly synthesized by co-precipitation.•Magnetic solid phase extraction (MSPE) for naphthols was developed based on Fe@LDH.•New method was simple, rapid, sensitive and easy to operate and separation.Magnetic Fe@MgAl-layered double hydroxides (MgAl-LDHs) composite was firstly synthesized by coating MgAl-layered double hydroxides on the surface of the dispersed nanoscale zero valent irons with co-precipitation method and characterized by transmission electron microscopy and X-ray diffraction techniques. The synthesized Fe@MgAl-LDHs nanoparticles were investigated for magnetic solid phase extraction (MSPE) of 1-naphthol and 2-naphthol from the water samples. The elutent containing 1-naphthol and 2-naphthol was analyzed by high performance liquid chromatography with variable wavelength detection (HPLC–UV). Under optimal conditions, there is good linear relationship between the concentration and the peak area in the range of 0.5–200 μg L−1 with the correlation coefficients (r2) above 0.998 for 1-naphthol and 2-naphthol. The limits of detection were 0.22 μg L−1 and 0.19 μg L−1 for 1-naphthol and 2-naphthol, respectively, and precisions were both below 2.5% (n = 6). The real water analysis demonstrated that the spiked recoveries were in the range of 79.2–80.9% (n = 3). All these results indicated that the developed MSPE–HPLC–UV method was proved to be an efficient tool for the analysis of naphthols.
Co-reporter:Qingxiang Zhou, Yuqin Wang, Junping Xiao, Huili Fan
Synthetic Metals 2016 Volume 212() pp:113-122
Publication Date(Web):February 2016
DOI:10.1016/j.synthmet.2015.12.008
•Fe3O4@polyaniline was prepared by a two-step oxidative polymerization.•Fe3O4@PANI has exhibited good adsorption for phenols by via π–π and electrostatic interaction.•Provided a highly efficient and low cost removal method for phenols.In present study, functional material, polyaniline coated Fe3O4 (Fe3O4@PANI), was synthesized using a simple two-step polymerization method, which was characterized by transmission electron microscopy(TEM), scanning electron microscope(SEM), FT-IR, X-ray diffraction(XRD), etc. Due to its structure, it would have strong affinities to the organics containing benzene ring because of π–π interactions and electrostatic interaction. This material was investigated to remove bisphenol A (BPA), α-naphthol and β-naphthol from water samples. The adsorption capacity (qmax) of the core–shell materials for bisphenol A (BPA), α-naphthol and β-naphthol was 23.0947, 28.7356, 9.1324 mg/g at 298 K, respectively. The kinetics results indicated that the adsorption process fit the pseudo-second-order kinetic model. The thermodynamic parameters ΔG for BPA, α-naphthol and β-naphthol were negative, suggesting that the adsorption reaction was spontaneous and endothermic in nature. The experimental results demonstrated that Fe3O4@PANI core–shell composites had great potential prospect for removing BPA, α-naphthol and β-naphthol from environmental water in the future.
Co-reporter:Yongli Liu, Qingxiang Zhou, Jing Li, Man Lei, Xiuyi Yan
Sensors and Actuators B: Chemical 2016 Volume 237() pp:597-604
Publication Date(Web):December 2016
DOI:10.1016/j.snb.2016.06.092
Lead is a well-known heavy metal element, and the resulted pollution has absorbed much more attention. It is important and also a great challenge to develop simple and effective methods for sensitive determination of lead ion (Pb2+) from water. Present study described a new chemosensor for the determination of lead ion based on water-soluble fluorescent carbon dots, which were prepared from chocolate using a simple and low-cost one-step hydrothermal method. The fluorescent carbon dots exhibited excitation-dependent behavior with the maximum excitation at 280 nm. This novel chemosensor demonstrated high sensitivity and selectivity for the detection of Pb2+ based on the efficient fluorescence quenching effect, which was ascribed to the special chelation between Pb2+ and hydroxyl groups on the surface of carbon dots. The developed chemosensor resulted in a limit of detection as low as 12.7 nM. In addition, the proposed method was validated with five real water samples, and good spiked recoveries were achieved. All these indicated that this new chemosensor had great prospect and would be a good alternative for the routine analysis of lead ion.
Co-reporter:Qingxiang Zhou, Zhenwen Zheng, Junping Xiao, Huili Fan
Talanta 2016 Volumes 156–157() pp:196-203
Publication Date(Web):15 August 2016
DOI:10.1016/j.talanta.2016.05.024
•Polyethyleneimine coated nanoscale zero valent iron was facile synthesized.•Fe@PEI based magnetic SPE was developed for determination of As(III) and As(V).•The method provided rapid separation and satisfied LODs.The magnetic nanomaterial Fe@polyethyleneimine (Fe@PEI) was successfully synthesized and used as an effective adsorbent material for magnetic solid phase extraction(MSPE) of As(III) and As(V) from water samples. Fe@SiO2 nanoparticles were prepared by one pot synthetic method using a borohydride reduction method, then modified with (3-chloropropyl)trimethoxysilane to obtain Fe@SiO2-Cl by chloropropylation, which was reacted with PEI to achieve Fe@polyethyleneimine (Fe@PEI). The microstructure and morphology of Fe@PEI were characterized by transmission electron microscoscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The experimental results showed that Fe@PEI demonstrated excellent adsorption for As(III) and As(V). Based on this fact, the determination method for these two arsenic species earned good limits of detection (LODs) of 0.002 μg L−1 and wide calibration curves in the concentration range from 0.008 to 0.2 μg L−1. The precisions of As (III) and As (V)were 1.95% and 2.55% (RSD, n=6), respectively. The proposed method was validated with real samples and the spiked recoveries were in the range of 82.7–98.3% and the accuracies were in the range of 2–13.3%. The results demonstrated that the developed MSPE method had good advantages such as simplicity, rapid separation, low cost, easy to reuse and high-quality analytical performances, which made it attractive for rapid and efficient extraction of inorganic arsenic species in the environmental water samples.
Co-reporter:Qingxiang Zhou, Zhi Fang
Analytica Chimica Acta 2015 Volume 869() pp:43-49
Publication Date(Web):15 April 2015
DOI:10.1016/j.aca.2015.02.019
•Graphene modified TiO2 nanotube array was prepared for enrichment.•A microextraction method was developed with graphene modified TiO2 nanotube array.•The developed method offered good LODs for carbamate pesticides in the range of 2.27–3.26 μg L−1.Graphene is a good adsorbent for organic pollutants, especially for compounds containing benzene rings. When used in TiO2 nanotube arrays for micro-solid phase extraction (μ-SPE), the combination of graphene’s strong adsorptive properties with its good separation capabilities results in excellent sample preconcentration performance. In the present study, graphene-modified TiO2 nanotube arrays were prepared by electrodeposition using a cyclic voltammetric reduction method. Four carbamate pesticides, including metolcarb, carbaryl, isoprocarb, and diethofencarb, were used as model analytes to validate the enrichment properties of the prepared adsorbent in μ-SPE. Factors affecting the enrichment efficiency of the μ-SPE procedure were optimized and included sample pH, elution solvents, salting-out effect, adsorption time and desorption time. Under optimal conditions, graphene-modified TiO2 nanotube arrays exhibited excellent enrichment efficiency for carbamate pesticides. The detection limits of these carbamate pesticides ranged from 2.27 to 3.26 μg L−1. The proposed method was validated using four environmental water samples, and yields of pesticides recovered from spiked test samples of the four analytes were in the range of 83.9–108.8%. These results indicate that graphene-modified TiO2 nanotube arrays exhibit good adsorption to the target pollutants, and the method described in this work could be used as a faster and easier alternative procedure for routine analysis of carbamate pesticides in real water samples.
Co-reporter:Qingxiang Zhou;Zhi Fang;Xiangkun Liao
Journal of Separation Science 2015 Volume 38( Issue 14) pp:2526-2531
Publication Date(Web):
DOI:10.1002/jssc.201500361
We describe a highly sensitive micro-solid-phase extraction method for the pre-concentration of six phthalate esters utilizing a TiO2 nanotube array coupled to high-performance liquid chromatography with a variable-wavelength ultraviolet visible detector. The selected phthalate esters included dimethyl phthalate, diethyl phthalate, dibutyl phthalate, butyl benzyl phthalate, bis(2-ethylhexyl)phthalate and dioctyl phthalate. The factors that would affect the enrichment, such as desorption solvent, sample pH, salting-out effect, extraction time and desorption time, were optimized. Under the optimum conditions, the linear range of the proposed method was 0.3–200 μg/L. The limits of detection were 0.04–0.2 μg/L (S/N = 3). The proposed method was successfully applied to the determination of six phthalate esters in water samples and satisfied spiked recoveries were achieved. These results indicated that the proposed method was appropriate for the determination of trace phthalate esters in environmental water samples.
Co-reporter:Qingxiang Zhou;Man Lei;Jing Li;Mengyun Wang;Danchen Zhao;An Xing ;Kuifu Zhao
Journal of Separation Science 2015 Volume 38( Issue 9) pp:1577-1583
Publication Date(Web):
DOI:10.1002/jssc.201401373
Selenium is an important element for human health, and it is present in many natural drinks and foods. Present study described a new method using dispersive liquid–liquid microextraction prior to high-performance liquid chromatography with a UV variable wavelength detector for the determination of the total selenium, Se(IV), Se(VI), and total organoselenium in tea samples. In the procedure, 2,3-diaminonaphthalene was used as the chelating reagent, 400 μL acetonitrile was used as the disperser solvent and 60 μL chlorobenzene was used as the extraction solvent. The complex of Se(IV) and 2,3-diaminonaphthalene in the final extracted phase was analyzed by high-performance liquid chromatography. The factors influencing the derivatization and microextraction were investigated. Under the optimal conditions, the limit of detection was 0.11 μg/L for Se(IV) and the linearity range was in the range of 0.5–40 μg/L. This method was successfully applied to the determination of selenium in four tea samples with spiked recoveries ranging from 91.3 to 100%.
Co-reporter:Qingxiang Zhou, Zhi Fang, Jing Li, Mengyun Wang
Microporous and Mesoporous Materials 2015 Volume 202() pp:22-35
Publication Date(Web):15 January 2015
DOI:10.1016/j.micromeso.2014.09.040
•Give a summary of the activity of TiO2 nanotube arrays in photocatalytic degradation.•Demonstrate the excellent of TiO2 nanotube arrays in environmental analytical chemistry.•TiO2 nanotube arrays have excellent prospect in energy field.TiO2 nanotube arrays, novel TiO2-based nanomaterials with unique chemical and physical properties, have been demonstrated to serve as multifunctional materials which show great promise in addressing many challenges in both environmental and energy technology fields. They have exhibited extraordinary catalytic abilities in several cases: in the degradation of environmental inorganic and organic pollutants to less toxic compounds, water splitting, and in the reduction of atmospheric CO2 levels by incorporation of CO2 into hydrocarbons, among others. Moreover, the wide absorption spectrum characteristics and distinct electrochemical properties of modified TiO2 nanotube arrays make them excellent candidates for use in solar cells and sensitive sensors for trace compounds, etc. This review focuses on the recent applications of TiO2 nanotube arrays in removal of pollutants, environmental analytical chemistry, water splitting, solar cells and CO2 conversion.
Co-reporter:Qingxiang Zhou and Zhi Fang
Analytical Methods 2015 vol. 7(Issue 7) pp:3277-3282
Publication Date(Web):03 Mar 2015
DOI:10.1039/C4AY03012E
Triazine herbicides are effective herbicides, which are widely used all over the world, but their residues pose a great threat to the environment and human health. Thus, it is crucial to develop a rapid and sensitive method for monitoring the triazine concentrations in the environment. The present study establishes a simple, sensitive and reliable method for determination of four triazine herbicides including atrazine, prometryn, propazine and simazine in water samples. Ordered titanium dioxide (TiO2) nanotube arrays were prepared using an anodization method and were then used as the adsorbent in the development of a micro-solid phase extraction for the enrichment of triazine herbicides before analysis using high performance liquid chromatography. The experimental results demonstrated that TiO2 nanotube arrays showed good adsorption of triazine herbicides, and the proposed method had satisfactory sensitivity with limits of detection in the range of 0.19–0.50 μg L−1. The proposed method was validated using four real environmental water samples and spiked recoveries were in the range of 84.3–101.9%. All the results demonstrated that the proposed method was an effective analytical tool and would be a useful method for the determination of such pollutants.
Co-reporter:Qingxiang Zhou, Zhi Fang
Talanta 2015 Volume 141() pp:170-174
Publication Date(Web):15 August 2015
DOI:10.1016/j.talanta.2015.04.016
•A new, simple and easy to operate method using TiO2 nanotube array was established for the analysis of sulfonamides.•SDBS enhanced the extraction efficiency of sulfonamides.•The developed method offered good LODs for sulfonamides in the range of 0.27–0.6 µg L−1.Sulfonamides are important antibiotics, and have achieved great applications. However they also impose serious threat on the environment and human health when they enter into environment by various ways. Present study developed a new determination method for six sulfonamides such as sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine, sulfamethoxazole and sulfafurazole in water samples, which was based on micro-solid phase extraction (μ-SPE) using TiO2 nanotube arrays as the adsorbent in combination with high performance liquid chromatography. Surfactant sodium dodecylbenzene sulfonate (SDBS) was used to enhance the extraction performance in this enrichment procedure. The parameters that affected the extraction efficiency had been investigated. Under the optimal conditions, it was observed that there were good linear relationships between the peak areas and the concentrations of the sulfonamides. The linear ranges were 1–200 μg L−1 for the six sulfonamides with the correlation coefficients in the range of 0.998–0.999. The repeatability of the proposed method was satisfactory in the range of 2.1–4.4% (RSD, n=6). The limits of detection (LODs) were in the range of 0.27–0.6 μg L−1. The proposed method was validated with real environmental samples, and the spiked recoveries were satisfied. These results indicated that the proposed method was a good tool for monitoring sulfonamides in the water samples.Figure optionsDownload full-size imageDownload as PowerPoint slide
Co-reporter:Qingxiang Zhou;Zhi Fang
Journal of Separation Science 2014 Volume 37( Issue 8) pp:1012-1017
Publication Date(Web):
DOI:10.1002/jssc.201301344
In this study, a simultaneous determination method for nitrogen-containing polycyclic aromatic hydrocarbons including 7-methylquinoline, acridine, 5,6-benzoquinoline, carbazole, and 9-methylcarbazole was developed. This method is based on a micro-solid phase extraction using TiO2 nanotube arrays as an adsorbent in combination with HPLC. Some factors that had an effect on the enrichment were optimized, such as sample pH, surfactant concentration, ion strength, type of eluent, equilibrium time, and desorption time. Under the optimized conditions, the linear ranges and LODs were in the range of 0.01–100 and 0.0035–0.81 μg/L, respectively. The precisions of the proposed method were <9.51% (RSD, n = 6). The developed method was validated with four real samples, and the spiked recoveries were in the range of 77–109.6%. All these results demonstrated that this novel micro-solid-phase extraction technique was a reliable alternative to conventional preconcentration method for the extraction and analysis of such nitrogen-containing polycyclic aromatic hydrocarbons in complex samples.
Co-reporter:Qingxiang Zhou and Zhi Fang
RSC Advances 2014 vol. 4(Issue 15) pp:7471-7475
Publication Date(Web):09 Jan 2014
DOI:10.1039/C3RA46478D
A novel and simple analytical method was developed for the rapid determination of three aromatic sulfur containing compounds including dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT) in water samples. Highly ordered TiO2 nanotube arrays were used as the adsorbent in the extraction procedure. The possible factors that would affect the extraction efficiency have been investigated in detail. Under the optimal conditions, TiO2 nanotube arrays showed a good adsorptive property for the target analytes. The experimental results demonstrated that low limits of detection (LODs, S/N = 3) of 0.02, 0.037, 0.038 μg L−1 for DBT, 4-MDBT, 4,6-DMDBT were achieved. This proposed method was validated with four real environmental water samples, and the results indicated that good spiked recoveries were in the range of 79.3% to 106.3%. All these results indicated that it is an effective and alternative tool for monitoring trace pollutants.
Co-reporter:Qingxiang Zhou;Kuifu Zhao ;An Xing
Journal of Separation Science 2014 Volume 37( Issue 22) pp:3347-3353
Publication Date(Web):
DOI:10.1002/jssc.201400778
Sudan Red pollutants have gained more attention in recent years. The present study described a simple and sensitive determination method for Sudan Red pollutants with dispersive liquid–liquid microextraction coupled to high-performance liquid chromatography. Chlorobenzene and ethanol were used as the extraction solvent and disperser solvent, respectively. The possible parameters such as the kind of solvents, ionic strength, and sample pH that could affect the enrichment have been optimized. Under the optimal conditions, the pollutants have been well enriched and the linear ranges of Sudan Red I and II were in the range of 0.3–40 μg/L, and the linear ranges of Sudan Red III and IV were in the range of 1.2–160 μg/L. The detection limits were in the range of 0.18–0.46 μg/L, and the precisions were in the range of 3.7–5.9%. All these demonstrated that the proposed method could be a good alternative for the routine analysis of Sudan Red pollutants in water samples.
Co-reporter:Qingxiang Zhou, Guoqing Wang and Guohong Xie
Analytical Methods 2014 vol. 6(Issue 1) pp:187-193
Publication Date(Web):15 Oct 2013
DOI:10.1039/C3AY40281A
This paper describes a new, rapid and reliable determination method for bisphenol A, 1-naphthol, 2-naphthol and 2,4-dinitrophenol using dispersive liquid-phase microextraction prior to high-performance liquid chromatography. In this method chlorobenzene was used as the extraction solvent and acetone was used as the disperser solvent. The parameters, which may influence the extraction efficiency such as the types and volumes of extraction solvent and disperser solvent, extraction time, sample pH, centrifugation time and salting-out effect, have been investigated. Under optimal conditions, there was a good linear relationship in the concentration range 0.25–50, 0.5–100, 0.75–150, and 1.5–300 μg L−1 for 2,4-dinitrophenol, 2-naphthol, 1-naphthol and bisphenol A, respectively. The limits of detection based on the ratio of signal-to-noise were equal to three (LODs, S/N = 3) in the range 0.11–0.62 μg L−1. Precision of the proposed method (RSDs, n = 6) were in the range 2.6–9.3%. The experimental results demonstrated that the present method lowered the LOQs compared to that of most existing methods and provided a simple and rapid analytical procedure. The analysis of real water samples spiked with two different concentrations resulted in good spiked recoveries in the range 86.8–118%. These results indicated that the proposed method would be competitive for the analysis of phenols.
Co-reporter:Qingxiang Zhou, Wei Wu and Yunrui Huang
Analytical Methods 2014 vol. 6(Issue 20) pp:8396-8402
Publication Date(Web):28 Aug 2014
DOI:10.1039/C4AY01412J
This paper reports on research to establish a micro-solid phase equilibrium extraction using a highly ordered titanium dioxide (TiO2) nanotube array for the pre-concentration and determination of environmental endocrine disruptors. The analysis was performed using high-performance liquid chromatography (HPLC) with fluorescence and ultraviolet detection. The experimental results showed that method detection limits (MDL) with fluorescence detection were 0.012, 0.033, 0.036 μg L−1 and MDL with ultraviolet detection were 0.022, 0.049, 0.093 μg L−1 for bisphenol A, 4-tert-octylphenol and 4-n-nonylphenol, respectively. The proposed method was successfully applied to the analysis of the target compounds in several environmental water samples. Good spiked recoveries in the range of 75.4–103.4% and 74.8–106.2% were obtained by using HPLC with fluorescence and ultraviolet detectors, respectively. These results showed that TiO2 nanotube arrays would be useful in the enrichment and determination of trace pollutants.
Co-reporter:Qingxiang Zhou and Yuanyuan Gao
Analytical Methods 2014 vol. 6(Issue 8) pp:2553-2559
Publication Date(Web):29 Jan 2014
DOI:10.1039/C3AY42254B
The present study describes a simple and sensitive method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by temperature-controlled ionic liquid dispersive liquid–liquid microextraction prior to high performance liquid chromatography with an ultraviolet detector. Three ionic liquids including 1-hexyl-3-methylimidazolium hexafluorophosphate [C6MIM][PF6], 1-benzyl-3-methylimidazolium hexafluorophosphate [C7MIM][PF6] and 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM][PF6] were investigated for enrichment, and the experimental results indicated that the best extraction efficiencies were achieved when [C8MIM][PF6] was used as the extraction solvent. Other factors affecting the extraction efficiency such as the volume of ionic liquid, heating temperature, extraction time, addition of 2-propanol, centrifugation time and ionic strength were also optimized. Under the optimal conditions, the detection limits of PAHs were in the range of 0.0005–0.88 μg L−1. The intra-day and inter-day precisions of the proposed method (RSDs, n = 6) were in the range of 2.7–7.4% and 5.5–11.4%, respectively. The proposed method was applied to the analysis of real environmental water samples and good spiked recoveries in the range of 83.5–118% were achieved. All these results indicate that the proposed method is a viable alternative to existing methods and would be very useful in the future.
Co-reporter:Qing-Xiang Zhou, Yuan-Yuan Gao
Chinese Chemical Letters 2014 Volume 25(Issue 5) pp:745-748
Publication Date(Web):May 2014
DOI:10.1016/j.cclet.2014.01.026
A temperature-controlled ionic liquid dispersive liquid-phase microextraction in combination with high performance liquid chromatography was developed for the enrichment and determination of triazine herbicides such as cyanazine, simazine, and atrazine in water samples. 1-Octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) was selected as the extraction solvent. Several experimental parameters were optimized. Under the optimal conditions, the linear range for cyanazine was in the concentration range of 0.5–80 μg/L and the linear range for simazine and atrazine was in the range of 1.0–100 μg/L. The limit of detection (LOD, S/N = 3) was in the ranges of 0.05–0.06 μg/L, and the intra day and inter day precision (RSDs, n = 6) was in the ranges of 3.2%–6.6% and 4.8%–8.9%, respectively. Four real water samples were analyzed with the developed method, and the experimental results showed that the spiked recoveries were satisfactory. All these exhibited that the developed method was a valuable tool for monitoring such pollutants.Present study established a temperature-controlled ionic liquid dispersive liquid-phase microextraction method using 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) in combination with high performance liquid chromatography, which has demonstrated good enrichment ability and high sensitivity for triazine herbicides such as cyanazine, simazine, and atrazine in water samples.
Co-reporter:Qingxiang Zhou, An Xing, Kuifu Zhao
Journal of Chromatography A 2014 1360() pp: 76-81
Publication Date(Web):
DOI:10.1016/j.chroma.2014.07.084
Co-reporter:Qingxiang Zhou;Guoqing Wang;Guohong Xie
Journal of Separation Science 2013 Volume 36( Issue 14) pp:2323-2329
Publication Date(Web):
DOI:10.1002/jssc.201300138
Benzoylurea (BU) insecticides have contributed greatly to the output of crops. Their residue in the environment put serious threats on human health and environmental safety. In this study, we have established a new, rapid, and reliable method for the monitoring of typical BU insecticides such as diflubenzuron, flufenoxuron, triflumuron, and chlorfluazuron with dispersive liquid–liquid microextraction prior to HPLC. Chlorobenzene and ethanol were employed as the extraction solvent and disperser solvent, respectively. The possible parameters which would influence the extraction efficiency such as the kinds and volumes of extraction and disperser solvents, extraction time, sample pH, centrifuging time, and salting-out effect were optimized in detail. Under the optimal conditions, the linear range of proposed method was in the range of 1.0–70 μg/L. The detection limits varied from 0.24 to 0.82 μg/L and the precision of the method was <6.5% (RSD, n = 6). The proposed method was validated with real water samples and satisfactory spiked recoveries were achieved. All these results indicate that the proposed method is a low cost, easy to operate, efficient, and sensitive method for the analysis of BU insecticides in water samples.
Co-reporter:Qingxiang Zhou, Yunrui Huang, Guohong Xie
Journal of Chromatography A 2012 Volume 1237() pp:24-29
Publication Date(Web):11 May 2012
DOI:10.1016/j.chroma.2012.02.066
Present study investigated the applicability of ordered TiO2 nanotube arrays for the enrichment and determination of polychlorinated biphenyls (PCBs) in water samples. A new and reliable method was developed for the preconcentration and determination of PCBs by micro-solid phase equilibrium extraction in combination with gas chromatography and electron capture detection (GC–ECD), which exploited the special physical and chemical properties of ordered TiO2 nanotube arrays. The experimental results indicated that low LODs were easily achieved in the range of 0.02–0.10 μg L−1 for PCB-28, PCB-52, PCB-101, PCB-153, PCB-138, and PCB-180. The proposed method was validated with several real water samples, and good spiked recoveries have been obtained in the range of 95.8–110.5%. The experimental results demonstrated that TiO2 nanotube arrays could be reused for over 200 times without the lost of the extraction efficiency. All these showed that TiO2 nanotube arrays would be very useful in the enrichment and determination of trace pollutants.Highlights► Investigate the applicability of ordered TiO2 nanotube arrays for the enrichment of PCBs. ► Establish a micro-solid phase equilibrium extraction for the enrichment and determination of PCBs. ► TiO2 nanotube arrays could be reused for over 200 times without lost of the extraction efficiency.
Co-reporter:Yuanyuan Gao;Guohong Xie;Ziwei Yao
Journal of Separation Science 2012 Volume 35( Issue 24) pp:3569-3574
Publication Date(Web):
DOI:10.1002/jssc.201200553
Present study described a simple, environmental benign, easy to operate, and determination method for fungicides including thiram, metalaxyl, diethofencarb, myclobutanil, and tebuconazole. The method is based on temperature-controlled ionic liquid dispersive liquid phase microextraction coupled to HPLC with ultraviolet detector. In the enrichment procedure, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM][PF6] was used as the extraction solvent. Variable affecting parameters such as the volume of [C8MIM][PF6], temperature, extraction time, centrifuging time, and salting-out effect have been optimized in detail. Under the optimal conditions, this method has been found to have good linear relationship in the concentration range of 1.0–100 μg/L and excellent detection sensitivity with LODs (S/N = 3) in the range of 0.32–0.79 μg/L. Precisions of proposed method were in the range of 3.7–5.9% for intraday and 7.8–11.0% for interday (RSDs, n = 6). The proposed method was used for the analysis of real water samples and good spiked recoveries at two different spiked levels were achieved in the range of 84.6–102%.
Co-reporter:Xuefeng Wang, Qingxiang Zhou and Mengxiao Zhai
Analytical Methods 2012 vol. 4(Issue 2) pp:394-398
Publication Date(Web):06 Dec 2011
DOI:10.1039/C1AY05458A
The present study focused on the investigation of the applicability of a new material, Zr doped TiO2 nanotubes, used as the solid phase extraction adsorbent for the enrichment of bisphenol A. The possible impacting parameters on the extraction such as the kind and volume of eluent, sample pH, sample flow rate, and sample volume were investigated in detail. Under the optimal extraction conditions, the proposed method had excellent linear range of 1–80 μg L−1 and the LOD was 0.016 μg L−1. The relative standard deviation at the concentration of 20 μg L−1 (RSDs, n = 6) was 2.9%. Four different real water samples were used for validation, and the spiked recoveries were satisfactory in the range of 102.9–108.8%, and all these results indicated that Zr doped TiO2 nanotubes had much better extraction performance and would be widely used in the future.
Co-reporter:Yunrui Huang, Qingxiang Zhou and Junping Xiao
Analyst 2011 vol. 136(Issue 13) pp:2741-2746
Publication Date(Web):24 May 2011
DOI:10.1039/C0AN01029D
This paper described a new method for the enrichment and determination of pyrethroid pesticides from environmental water samples with ordered TiO2 nanotube array micro-solid phase equilibrium extraction (μ-SPEE) prior to gas chromatography (GC) with electron capture detection (ECD). Several factors such as the anodization voltage, the kind of organic solvents, sample pH, equilibrium extraction time, desorption time and salting-out effect were optimized. Under the optimal conditions, ordered TiO2 nanotube arrays demonstrated excellent merits on the preconcentration of pyrethroid pesticides and good detection limits were achieved as 0.018, 0.020, 0.031, 0.041, and 0.070 μg L−1 for bifenthrin, fenpropathrin, cyhalothrin, fenvalerate, and deltamethrin, respectively. Four real water samples were used to validate the proposed method and the spiked recoveries were over the range of 81.9–110.6%. Compared to conventional solid phase extraction (SPE), the present method showed better recoveries and good reproducibility. These results showed that this μ-SPEE technique could be an important alternative to multistep SPE for the extraction and determination of such analytes in complex samples and become a useful tool in monitoring such analytes in the environment.
Co-reporter:Qingxiang Zhou, Yuanyuan Gao, Junping Xiao and Guohong Xie
Analytical Methods 2011 vol. 3(Issue 3) pp:653-658
Publication Date(Web):03 Feb 2011
DOI:10.1039/C0AY00619J
This paper established a new determination method for phenols using temperature-controlled ionic liquid dispersive liquid-phase microextraction prior to high-performance liquid chromatography. In this experiment, 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) was employed as the extraction solvent for the enrichment of 2-chlorophenol, 2-naphthol, 2,4-dinitrophenol, and 2,4-dichlorophenol. Parameters that may affect the extraction efficiency including the volume of [C8MIM][PF6], dissoluble temperature, extraction time, sample pH, amount of ethanol, centrifugation time and salting-out effect have been investigated in detail. Under the optimal conditions, they have good linear relationships over the concentration range of 1.0-100 ng mL−1 for 2-chlorophenol, 2-naphthol, 2,4-dinitrophenol, and 1.5-150 ng mL−1 for 2,4-dichlorophenol, and excellent detection sensitivity with limits of detection (LOD, S/N = 3) in the range of 0.27–0.68 μg L−1. Intra day and inter day precisions of the proposed method (RSDs, n = 6) were 2.1–3.7% and 5.1–7.2%, respectively. The proposed method has been successfully applied to analyze real water samples spiked with two different concentrations and good spiked recoveries over the range of 85.8–117.0% were obtained. These results indicated that the proposed method would be competitive in the analysis of phenols in the future.
Co-reporter:Qingxiang Zhou, Xiaoguo Zhang and Guohong Xie
Analytical Methods 2011 vol. 3(Issue 8) pp:1815-1820
Publication Date(Web):18 Jul 2011
DOI:10.1039/C1AY05137G
A simple, rapid and efficient method is described for the simultaneous pre-concentration and determination of phthalate esters and pyrethroid insecticides in water samples by temperature controlled ionic liquid dispersive liquid phase microextraction in combination with high performance liquid chromatography. In this procedure, only ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM][PF6] was used for the enrichment. The proposed method successfully overcomes the disadvantages of conventional single drop liquid phase microextraction and dispersive liquid-liquid microextraction such as the instability of the suspending drop and the use of toxic solvents, and requires a smaller extraction volume. Factors such as volume of [C8MIM][PF6], sample pH, extraction time, centrifugation time, and temperature and salting-out effect were systematically investigated and optimized. The detection limits obtained for phthalate esters and pyrethroid insecticides were in the range of 0.23–0.47 μg L−1 and the precisions were in the range of 2.2–5.9% (n = 6). Real water samples were used for validating the proposed method and satisfactory results were achieved.
Co-reporter:Qingxiang Zhou, Xiaoguo Zhang and Guohong Xie
Analytical Methods 2011 vol. 3(Issue 2) pp:356-361
Publication Date(Web):15 Dec 2010
DOI:10.1039/C0AY00570C
This paper developed a new method with temperature controlled ionic liquid dispersive liquid-phase microextraction for the determination of pyrethroid insecticides such as fenpropathrin, fenvalerate and bifenthrin in water samples. The effect of alkyl chain length of ionic liquid 1-alkyl-3-methylimidazolium hexafluorophosphate and other parameters such as sample pH, temperature, salting-out effect and sample volume on the extraction efficiency were investigated in detail. Four different alkyl chain length ionic liquids ([CnMIM][PF6], n = 4, 6, 7, 8) were tested. The experimental results demonstrated that the alkyl chain length of ionic liquids (ILs) did have an important role on the extraction efficiency. The experimental results indicated that the longer alkyl chain length of ILs resulted in better extraction efficiency. Among the four ILs, 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM] [PF6] was the best one for extraction of the target analytes. Under the optimized conditions, three pyrethroid insecticides had limits of detection (LOD, S/N = 3) in the range of 0.34∼0.48 μg L−1. The precisions of the proposed method (RSDs, n = 6) with a spiked concentration of 20 μg L−1 were in the range of 2.0∼3.4%. The proposed method was evaluated with real water samples spiked at a concentration of 10 ng mL−1 and good spiked recoveries over the range of 89.2∼102.7% were obtained.
Co-reporter:Qingxiang Zhou, Yuanyuan Gao, Guohong Xie
Talanta 2011 Volume 85(Issue 3) pp:1598-1602
Publication Date(Web):15 September 2011
DOI:10.1016/j.talanta.2011.06.050
Present study described a simple, sensitive, and viable method for the determination of bisphenol A, 4-n-nonylphenol and 4-tert-octylphenol in water samples using temperature-controlled ionic liquid dispersive liquid-phase microextraction coupled to high performance liquid chromatography-fluorescence detector. In this experiment, 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) was used as the extraction solvent, and bisphenol A, 4-n-nonylphenol and 4-tert-octylphenol were selected as the model analytes. Parameters affecting the extraction efficiency such as the volume of [C8MIM][PF6], dissolving temperature, extraction time, sample pH, centrifuging time and salting-out effect have been investigated in detail. Under the optimized conditions, good linear relationship was found in the concentration range of 1.0–100 μg L−1 for BPA, 1.5–150 μg L−1 for 4-NP, and 3–300 μg L−1 for 4-OP, respectively. Limits of detection (LOD, S/N = 3) were in the range of 0.23–0.48 μg L−1. Intra day and inter day precisions (RSDs, n = 6) were in the range of 4.6–5.5% and 8.5–13.3%, respectively. This method has been also successfully applied to analyze the real water samples at two different spiked concentrations and excellent results were obtained.
Co-reporter:Yunrui Huang;Guohong Xie;Haijin Liu;Haiying Lin
Microchimica Acta 2011 Volume 172( Issue 1-2) pp:109-115
Publication Date(Web):2011 February
DOI:10.1007/s00604-010-0472-4
A new, simple and sensitive method was established for solid-phase extraction of benzoylurea insecticides including diflubenzuron, chlorbenzuron, triflumuron, flufenoxuron, and chlorfluazuron in water samples using TiO2 nanotubes cartridge prior to their determination by liquid chromatography. The parameters influencing the extraction were investigated and optimized. Under optimal conditions, a good linearity was found between the concentration and the peak area in the range from 0.2 to 40 μg L-1 (r2 > 0.99), and detection limits were in the range from 0.062 to 0.21 μg L-1. Real water samples were used for validating the method and recoveries of spiked samples were over the range from 82.0 to 100%. The results indicated that TiO2 nanotubes repesented an attractive alternative sorbent for the enrichment and trace analysis of such pollutants.
Co-reporter:Qingxiang Zhou, Yuanyuan Gao, Huahua Bai, Guohong Xie
Journal of Chromatography A 2010 Volume 1217(Issue 31) pp:5021-5025
Publication Date(Web):30 July 2010
DOI:10.1016/j.chroma.2010.05.060
Present study developed a new method for the sensitive determination of pyrethroid insecticides with solid phase extraction in combination with high performance liquid chromatography and UV detector. SiO2 microspheres, a new SiO2 based material, was investigated for the enrichment ability and applicability as the solid phase extraction sorbent. Four pyrethroid pesticides such as fenpropathrin, cyhalothrin, fenvalevate and biphenthrin were used as the target analytes. Parameters that maybe influence the extraction efficiency such as the eluent type and its volume, sample flow rate, sample pH, and the sample volume were optimized in detail, and the optimal conditions were as followed: sample volume, 100 mL; concentration of methanol, 30%; acetone volume, 5 mL; sample flow rate, 4.2 mL min−1; sample pH, 7. The experimental results indicated that there was good linearity in the concentration range of 0.1–50 μg L−1 except biphenthrin in the range of 0.05–25 μg L−1. The detection limits for fenpropathrin, cyhalothrin, fenvalevate and biphenthrin were in the range of 0.02–0.08 μg L−1. The intra-day and day to day precisions (RSDs, n = 6) were in the ranges of 2.6–4.4% and 5.3–7.2%, respectively. The method was validated with five real environmental water samples, and all these results proved that proposed method could be used as a good alternative for the routine analysis for such pollutants in environmental samples.
Co-reporter:Yunrui Huang;Junping Xiao;Guohong Xie
Journal of Separation Science 2010 Volume 33( Issue 14) pp:2184-2190
Publication Date(Web):
DOI:10.1002/jssc.201000147
Abstract
This article described a new method for the sensitive determination of organophosphorus pesticides in water samples using SPE in combination with GC-flame photometric detection. In the procedure of method development, TiO2 nanotubes were used as SPE adsorbents for the enrichment of organophosphorus pesticides from water samples. Several factors, such as eluent and its volume, sample pH, sample volume, sample flow rate, and concentration of humic acid, were optimized. Under the optimal conditions, the proposed method had good linear ranges as 0.1–40 μg/L for each of them, LOD of 0.11, 0.014, and 0.0025 μg/L, and LOQs of 0.37, 0.047, and 0.0083 μg/L for chlorpyrifos, phorate, and methyl parathion, respectively. The proposed method was validated with real environmental water samples and the spiked recoveries were over the range of 86.5–115.1%. All these results indicated that TiO2 nanotubes, as a new SPE adsorbent, would be used widespread for the preconcentraiton and determination of environmental pollutants in the future.
Co-reporter:Qingxiang Zhou;Xiaoguo Zhang
Journal of Separation Science 2010 Volume 33( Issue 23-24) pp:3734-3740
Publication Date(Web):
DOI:10.1002/jssc.201000443
Abstract
This paper describes a new method for rapid and sensitive determination of diflubenzuron, flufenoxuron, triflumuron and chlorfluazuron in water samples by ultrasound-assisted ionic liquid dispersive liquid-phase microextraction in combination with HPLC. Ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) was used as the extraction solvent for the enrichment of four benzoylurea (BU) pesticides. Factors such as volume of [C6MIM][PF6], sonication time, sample pH, extraction time, centrifuging time and salting-out effect were systematically investigated. Under the optimum conditions, an excellent linear relationship was achieved in the range of 1.0–100 μg/L. The detection limits varied from 0.21 to 0.45 μg/L and the precision of the method was below 6.9% (RSD, n=6). The proposed method was successfully applied for the determination of these BU pesticides in water samples and excellent spiked recoveries were achieved. All these results demonstrated that this procedure provided a new simple, rapid, easy to operate, efficient and sensitive method for the analysis of BU pesticides in aqueous samples.
Co-reporter:Qingxiang Zhou, Jinli Mao, Junping Xiao and Guohong Xie
Analytical Methods 2010 vol. 2(Issue 8) pp:1063-1068
Publication Date(Web):24 Jun 2010
DOI:10.1039/C0AY00250J
This paper describes a new method for rapid and sensitive determination of paraquat (PQ) and diquat (DQ) by solid phase extraction with N doped TiO2 nanotubes cartridge prior to capillary electrophoresis. Several factors that would affect the extraction efficiency were optimized and the optimal conditions were as followed: sample volume, 500 mL; sample pH, pH 9.0; eluant, 1 mol L−1 HCl/methanol: 70/30 (v/v); eluant volume, 3 mL; sample flow rate, 2.5 mL min−1. Under the optimal conditions, the linear ranges and detection limits were 2.5–100 μgL−1, 5–50 μg L−1 and 1.95 μg L−1, 2.59 μg L−1 for PQ and DQ, respectively. The proposed method was successfully applied to the analysis of PQ and DQ in several environmental water samples, and the spiked recoveries were over the range of 84.15–95.38%. These results indicated that N doped TiO2 nanotubes had better enrichment ability for PQ and DQ as a novel SPE adsorbent material, and maybe have good application prospect for monitoring other pollutants in the environment.
Co-reporter:Qingxiang Zhou;Yuanyuan Gao;Junping Xiao;Guohong Xie
Chromatographia 2010 Volume 72( Issue 11-12) pp:1067-1071
Publication Date(Web):2010 December
DOI:10.1365/s10337-010-1794-4
A new method has been developed for the determination of metalaxyl, myclobutanil, and tebuconazole in environmental water samples with preconcentration by cartridges packed with SiO2 microspheres prior to LC. Several parameters such as the volume and composition of eluent, sample flow rate, sample pH, and sample volume were optimized. Under the optimal conditions, excellent detection limits (S/N = 3) and precision (RSD, n = 6) were 0.02 ng mL−1, 1.3% for metalaxyl, 0.02 ng mL−1, and 2.4% for myclobutanil and 0.08 ng mL−1 and 4.3% for tebuconazole, respectively. The method was applied to the analysis of real-water samples, and satisfactory results were obtained. The average spiked recoveries were in the range of 86.3–97.5%. These results indicate that SiO2 microspheres have great potential to be used as a novel solid phase extraction adsorbent that could have wide applications in the environmental field.
Co-reporter:Yongli Liu, Qingxiang Zhou, Yongyong Yuan, Yalin Wu
Carbon (May 2017) Volume 115() pp:
Publication Date(Web):May 2017
DOI:10.1016/j.carbon.2017.01.035
Fluorescent carbon dots (CDs) have been a promising star in analytical and environmental fields. Present study designed a new bright-blue fluorescent carbon dots with sodium citrate and polyacrylamide by a hydrothermal method. The obtained CDs had an average diameter of 2.4 nm and exhibited excitation-independent property. The experimental results demonstrated that the bright-blue fluorescent CDs exhibited “off-on” property with Pb2+ and pyrophosphate (PPi), which proved that it was a good fluorescent probe for the determination of Pb2+ and PPi. The fluorescence intensity of CDs was significantly quenched by Pb2+ (turn-off) through forming CDs/Pb2+ complexes via an inner filter effect, and the fluorescence intensity of CDs/Pb2+ system was completely resumed by PPi (turn-on) owing to the release of CDs from the CDs/Pb2+ complexes due to higher binding force of PPi to Pb2+. The detection limits were 4.6 nM for Pb2+ and 54 nM for PPi, respectively. The probe was successfully validated with real water samples and human urine. The results showed that this the probe was facile, rapid and exhibited high sensitivity, selectivity, repeatability and stability. This “off-on” fluorescent probe based on CDs provided a promising platform for environmental and biological sensing applications.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 20) pp:
Publication Date(Web):
DOI:10.1039/C4AY01412J
This paper reports on research to establish a micro-solid phase equilibrium extraction using a highly ordered titanium dioxide (TiO2) nanotube array for the pre-concentration and determination of environmental endocrine disruptors. The analysis was performed using high-performance liquid chromatography (HPLC) with fluorescence and ultraviolet detection. The experimental results showed that method detection limits (MDL) with fluorescence detection were 0.012, 0.033, 0.036 μg L−1 and MDL with ultraviolet detection were 0.022, 0.049, 0.093 μg L−1 for bisphenol A, 4-tert-octylphenol and 4-n-nonylphenol, respectively. The proposed method was successfully applied to the analysis of the target compounds in several environmental water samples. Good spiked recoveries in the range of 75.4–103.4% and 74.8–106.2% were obtained by using HPLC with fluorescence and ultraviolet detectors, respectively. These results showed that TiO2 nanotube arrays would be useful in the enrichment and determination of trace pollutants.
Co-reporter:Qingxiang Zhou, Xiaoguo Zhang and Guohong Xie
Analytical Methods (2009-Present) 2011 - vol. 3(Issue 8) pp:NaN1820-1820
Publication Date(Web):2011/07/18
DOI:10.1039/C1AY05137G
A simple, rapid and efficient method is described for the simultaneous pre-concentration and determination of phthalate esters and pyrethroid insecticides in water samples by temperature controlled ionic liquid dispersive liquid phase microextraction in combination with high performance liquid chromatography. In this procedure, only ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM][PF6] was used for the enrichment. The proposed method successfully overcomes the disadvantages of conventional single drop liquid phase microextraction and dispersive liquid-liquid microextraction such as the instability of the suspending drop and the use of toxic solvents, and requires a smaller extraction volume. Factors such as volume of [C8MIM][PF6], sample pH, extraction time, centrifugation time, and temperature and salting-out effect were systematically investigated and optimized. The detection limits obtained for phthalate esters and pyrethroid insecticides were in the range of 0.23–0.47 μg L−1 and the precisions were in the range of 2.2–5.9% (n = 6). Real water samples were used for validating the proposed method and satisfactory results were achieved.
Co-reporter:
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 2) pp:
Publication Date(Web):
DOI:10.1039/C1AY05458A
The present study focused on the investigation of the applicability of a new material, Zr doped TiO2 nanotubes, used as the solid phase extraction adsorbent for the enrichment of bisphenol A. The possible impacting parameters on the extraction such as the kind and volume of eluent, sample pH, sample flow rate, and sample volume were investigated in detail. Under the optimal extraction conditions, the proposed method had excellent linear range of 1–80 μg L−1 and the LOD was 0.016 μg L−1. The relative standard deviation at the concentration of 20 μg L−1 (RSDs, n = 6) was 2.9%. Four different real water samples were used for validation, and the spiked recoveries were satisfactory in the range of 102.9–108.8%, and all these results indicated that Zr doped TiO2 nanotubes had much better extraction performance and would be widely used in the future.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 8) pp:NaN2559-2559
Publication Date(Web):2014/01/29
DOI:10.1039/C3AY42254B
The present study describes a simple and sensitive method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by temperature-controlled ionic liquid dispersive liquid–liquid microextraction prior to high performance liquid chromatography with an ultraviolet detector. Three ionic liquids including 1-hexyl-3-methylimidazolium hexafluorophosphate [C6MIM][PF6], 1-benzyl-3-methylimidazolium hexafluorophosphate [C7MIM][PF6] and 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM][PF6] were investigated for enrichment, and the experimental results indicated that the best extraction efficiencies were achieved when [C8MIM][PF6] was used as the extraction solvent. Other factors affecting the extraction efficiency such as the volume of ionic liquid, heating temperature, extraction time, addition of 2-propanol, centrifugation time and ionic strength were also optimized. Under the optimal conditions, the detection limits of PAHs were in the range of 0.0005–0.88 μg L−1. The intra-day and inter-day precisions of the proposed method (RSDs, n = 6) were in the range of 2.7–7.4% and 5.5–11.4%, respectively. The proposed method was applied to the analysis of real environmental water samples and good spiked recoveries in the range of 83.5–118% were achieved. All these results indicate that the proposed method is a viable alternative to existing methods and would be very useful in the future.
Co-reporter:Qingxiang Zhou, Jinli Mao, Junping Xiao and Guohong Xie
Analytical Methods (2009-Present) 2010 - vol. 2(Issue 8) pp:NaN1068-1068
Publication Date(Web):2010/06/24
DOI:10.1039/C0AY00250J
This paper describes a new method for rapid and sensitive determination of paraquat (PQ) and diquat (DQ) by solid phase extraction with N doped TiO2 nanotubes cartridge prior to capillary electrophoresis. Several factors that would affect the extraction efficiency were optimized and the optimal conditions were as followed: sample volume, 500 mL; sample pH, pH 9.0; eluant, 1 mol L−1 HCl/methanol: 70/30 (v/v); eluant volume, 3 mL; sample flow rate, 2.5 mL min−1. Under the optimal conditions, the linear ranges and detection limits were 2.5–100 μgL−1, 5–50 μg L−1 and 1.95 μg L−1, 2.59 μg L−1 for PQ and DQ, respectively. The proposed method was successfully applied to the analysis of PQ and DQ in several environmental water samples, and the spiked recoveries were over the range of 84.15–95.38%. These results indicated that N doped TiO2 nanotubes had better enrichment ability for PQ and DQ as a novel SPE adsorbent material, and maybe have good application prospect for monitoring other pollutants in the environment.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 1) pp:NaN193-193
Publication Date(Web):2013/10/15
DOI:10.1039/C3AY40281A
This paper describes a new, rapid and reliable determination method for bisphenol A, 1-naphthol, 2-naphthol and 2,4-dinitrophenol using dispersive liquid-phase microextraction prior to high-performance liquid chromatography. In this method chlorobenzene was used as the extraction solvent and acetone was used as the disperser solvent. The parameters, which may influence the extraction efficiency such as the types and volumes of extraction solvent and disperser solvent, extraction time, sample pH, centrifugation time and salting-out effect, have been investigated. Under optimal conditions, there was a good linear relationship in the concentration range 0.25–50, 0.5–100, 0.75–150, and 1.5–300 μg L−1 for 2,4-dinitrophenol, 2-naphthol, 1-naphthol and bisphenol A, respectively. The limits of detection based on the ratio of signal-to-noise were equal to three (LODs, S/N = 3) in the range 0.11–0.62 μg L−1. Precision of the proposed method (RSDs, n = 6) were in the range 2.6–9.3%. The experimental results demonstrated that the present method lowered the LOQs compared to that of most existing methods and provided a simple and rapid analytical procedure. The analysis of real water samples spiked with two different concentrations resulted in good spiked recoveries in the range 86.8–118%. These results indicated that the proposed method would be competitive for the analysis of phenols.
Co-reporter:Qingxiang Zhou, Xiaoguo Zhang and Guohong Xie
Analytical Methods (2009-Present) 2011 - vol. 3(Issue 2) pp:NaN361-361
Publication Date(Web):2010/12/15
DOI:10.1039/C0AY00570C
This paper developed a new method with temperature controlled ionic liquid dispersive liquid-phase microextraction for the determination of pyrethroid insecticides such as fenpropathrin, fenvalerate and bifenthrin in water samples. The effect of alkyl chain length of ionic liquid 1-alkyl-3-methylimidazolium hexafluorophosphate and other parameters such as sample pH, temperature, salting-out effect and sample volume on the extraction efficiency were investigated in detail. Four different alkyl chain length ionic liquids ([CnMIM][PF6], n = 4, 6, 7, 8) were tested. The experimental results demonstrated that the alkyl chain length of ionic liquids (ILs) did have an important role on the extraction efficiency. The experimental results indicated that the longer alkyl chain length of ILs resulted in better extraction efficiency. Among the four ILs, 1-octyl-3-methylimidazolium hexafluorophosphate [C8MIM] [PF6] was the best one for extraction of the target analytes. Under the optimized conditions, three pyrethroid insecticides had limits of detection (LOD, S/N = 3) in the range of 0.34∼0.48 μg L−1. The precisions of the proposed method (RSDs, n = 6) with a spiked concentration of 20 μg L−1 were in the range of 2.0∼3.4%. The proposed method was evaluated with real water samples spiked at a concentration of 10 ng mL−1 and good spiked recoveries over the range of 89.2∼102.7% were obtained.
Co-reporter:Qingxiang Zhou, Yuanyuan Gao, Junping Xiao and Guohong Xie
Analytical Methods (2009-Present) 2011 - vol. 3(Issue 3) pp:
Publication Date(Web):
DOI:10.1039/C0AY00619J
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