Co-reporter:Ciprian Briciu-Burghina, Brendan Heery, Fiona Regan
Analytica Chimica Acta 2017 Volume 964(Volume 964) pp:
Publication Date(Web):29 April 2017
DOI:10.1016/j.aca.2017.02.035
•Rapid protocol (less than 75 min) for E. coli detection in environmental waters developed.•Optimization of sample preparation for best performance including E. coli recovery and extraction of GUS marker enzyme.•Evaluation of this protocol against the standard method and a literature rapid method.To achieve active management of bathing areas and to reduce risk associated with the presence of fecal pollution, tests capable of rapid on-site assessment of microbiological water quality are required. A protocol for the recovery and detection of fecal pollution indicator bacteria, E. coli, using β-glucuronidase (GUS) activity was developed. The developed protocol involves two main steps: sample preparation and GUS activity measurement. In the sample preparation step, syringe filters were used with a dual purpose, for the recovery and pre-concentration of E. coli from the water matrix and as μL reactors for bacteria lysis and GUS extraction. Subsequently, GUS activity was measured using a continuous fluorometric method developed previously. The optimum GUS recovery conditions for the sample preparation step were found to be 100 μL PELB (supplemented with 1 mg mL−1 lysozyme and 20 mM DTT) at 37 °C for 30 min. The protocol was evaluated on environmental samples (fresh and seawater) against an establish GUS assay method (Coliplage®). GUS activities corresponding to samples containing as low as 26 MPN E. coli 100 mL−1 were detected for the seawater sample and as low as 110 MPN E. coli 100 mL−1 for the freshwater samples. By comparison with the Coliplage® method, this protocol offered an improvement in the measured GUS activities of 3.1 fold for freshwater samples and 4.1 fold for seawater samples. Furthermore, the protocol developed here, has a time-to-result of 75 min, and successfully addresses the requirement for tests capable of rapid assessment of microbiological water quality.Download high-res image (378KB)Download full-size image
Co-reporter:G. Duffy;F. Regan
Analyst (1876-Present) 2017 vol. 142(Issue 23) pp:4355-4372
Publication Date(Web):2017/11/20
DOI:10.1039/C7AN00840F
The demand for autonomous sensors for unattended, continuous nutrient monitoring in water is rapidly growing with the increasing need for more frequent and widespread environmental pollution monitoring. Legislative bodies, local authorities and industries all require frequent water quality monitoring, however, this is time and labour intensive, and an expensive undertaking. Autonomous sensors allow for frequent, unattended data collection. While this solves the time and labour intensive aspects of water monitoring, sensors can be very expensive. Development of low-cost sensors is essential to realise the concept of Internet of Things (IoT). However there is much work yet to be done in this field. This article reviews current literature on the research and development efforts towards deployable autonomous sensors for phosphorus (in the form of phosphate) and nitrogen (in the form of nitrate), with a focus on analytical performance and cost considerations. Additionally, some recent sensing approaches that could be automated in the future are included, along with an overview of approaches to monitoring both nutrients. These approaches are compared with standard laboratory methods and also with commercially available sensors for both phosphate and nitrate. Application of nutrient sensors in agriculture is discussed as an example of how sensor networks can provide improvements in decision making.
Co-reporter:L. Jones;B. Kinsella;K. Forde;A. Furey;F. Regan
Analytical Methods (2009-Present) 2017 vol. 9(Issue 28) pp:4167-4174
Publication Date(Web):2017/07/20
DOI:10.1039/C7AY00704C
Much research has been carried out on the analysis of chemical residue pollutants in the aquatic environment including drinking water, lakes, rivers, ground water, estuaries and coastal zones. However, few studies report the analysis of wastewater for the presence of chemical pollutants, including pesticides, even though this is an important issue because wastewater can be a major point source input of pollutants to the environment. The aim of this research was to develop an analytical method for the detection and confirmation of 13 pesticide residues in wastewater. All 13 pesticides are included on the EU priority pesticides list outlined the Water Framework Directive (2000/60/EC). Pesticides were extracted from wastewater using solid-phase extraction (SPE) on polymeric cartridges containing hydrophilic and lipophilic functional groups capable of retaining pesticides with diverse physico-chemical properties. The pesticides were eluted with organic solvent and concentrated by evaporation prior to analysis by liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS) operated in electrospray ionization (ESI) mode. LC-MS/MS runs both positive and negative modes were carried out for each sample. Recovery of the 13 pesticides was typically greater than 80%. All 13 pesticides were found to be linear over the concentration range 1 to 100 ng mL−1 with linear regression values (R2) typically greater than 0.99. The limit of detection (LOD) of the method was 1 ng mL−1, except for chlorpyrifos (5 ng mL−1). 11 isotopically labelled internal standards were included in the method to improve accuracy and precision. The final method was used to analyse wastewater samples collected from seven WWTPs over a period of four months. Several pesticides were found to be present in the samples tested at each WWTP. A total of 204 samples were collected from 68 sampling events between 2011 and 2012. Exceedances were detected at each of the seven sites in this study, with diuron, atrazine and simazine most frequently occurring.
Co-reporter:Lisa Jones;David Styles;Brian Kinsella
Water Conservation Science and Engineering 2017 Volume 1( Issue 4) pp:209-221
Publication Date(Web):2017 March
DOI:10.1007/s41101-016-0014-y
Risk indices have recently emerged as an effective and efficient tool in the area of water quality monitoring with new indices taking in vast quantities of data and facilitating the development of more targeted water monitoring programs. With the Water Framework Directive demanding that monitoring requirements for a list of priority substances be met, achieving ‘good’ status in all water bodies by 2015, there is a strong need for improved monitoring programmes. In order to improve future monitoring programmes by making the process more ‘targeted’ a simple risk-based index for the occurrence of priority substances in wastewater treatment plant effluent was devised. This index was developed through the collection of an extensive list of documents relating to priority substance emission factors. These included wastewater treatment licence applications, trade effluent licences, traffic data, rainfall data, and census data. It was found that by relating data from each of these sources to historic occurrence data, it was possible to conceptualise and develop a ranking of risk of occurrence of priority substances. Validation of this index was carried out using data from a 24-month sampling plan at nine sites in two counties in Ireland representative of different pressures, i.e. agricultural, industrial and domestic. This work has allowed for the compilation of a large dataset of emission factor and priority substance occurrence in Ireland where none previously existed. For the first time, a risk-based index has been developed for Irish wastewater treatment plant effluents. Together, the index and dataset can be used by policy makers and inform the development of future priority substance monitoring programmes.
Co-reporter:A. C. Power;A. Barrett;J. Abubakar;L. J. Suarez;L. Ryan;D. Wencel;T. Sullivan;F. Regan
Advanced Engineering Materials 2016 Volume 18( Issue 1) pp:76-82
Publication Date(Web):
DOI:10.1002/adem.201500112
The performance of optical devices is dependent on their optical transparency (OT). This is evident when such devices are exposed to environmental conditions that can reduce OT. The development of a robust, transparent and self-cleaning coating is highly desirable, for applications likeoptical windows and solar panels. This work reports the design of such coatings based on a hydrophobic thin film fabricated using a sol-gel process. Coating properties were optimised by modification of the surface topography of the coatings, achieved by the incorporation of silica nanoparticles(NPs). The coating was characterised by water contact angle(WCA), scanning electron microscopy(SEM) and white light interferometry (WLI). The efficacy and robustness of the coating foroptical application was assessed.
Co-reporter:Brendan Heery, Ciprian Briciu-Burghina, Dian Zhang, Gillian Duffy, Dermot Brabazon, Noel O’Connor, Fiona Regan
Talanta 2016 Volume 148() pp:75-83
Publication Date(Web):1 February 2016
DOI:10.1016/j.talanta.2015.10.035
•β-d-Glucuronidase (GUS) enzyme assay in a field portable detection system.•Novel syringe filter based lysing protocol applied.•6-Chloro-4-Methyl-Umbelliferyl-β-d-Glucuronide (6-CMUG) used as substrate.•ColiSense; a rapid (75 min) on-site alternative to culture based E.coli assays.•Same day analysis of recreational waters for bathing water directive compliance.A sensitive field-portable fluorimeter with incubating capability and triplicate sample chambers was designed and built. The system was optimised for the on-site analysis of E. coli in recreational waters using fluorescent based enzyme assays. The target analyte was β-d-Glucuronidase (GUS) which hydrolyses a synthetic substrate 6-Chloro-4-Methyl-Umbelliferyl-β-d-Glucuronide (6-CMUG) to release the fluorescent molecule 6-Chloro-4-Methyl-Umbelliferyl (6-CMU). The system was calibrated with 6-CMU standards. A LOD of 5 nM and a resolution of less than 1 nM was determined while enzyme kinetic tests showed detection of activities below 1 pmol min−1 mL−1 of sample. A field portable sample preparation, enzyme extraction protocol and continuous assay were applied with the system to analyse freshwater and marine samples. Results from a one day field trial are shown which demonstrated the ability of the system to deliver results on-site within a 75 min period.
Co-reporter:Ciprian Briciu-Burghina, Brendan Heery and Fiona Regan
Analyst 2015 vol. 140(Issue 17) pp:5953-5964
Publication Date(Web):30 Jul 2015
DOI:10.1039/C5AN01021G
E. coli β-glucuronidase (GUS) activity assays are routinely used in fields such as plant molecular biology, applied microbiology and healthcare. Methods based on the optical detection of GUS using synthetic fluorogenic substrates are widely employed since they don't require expensive instrumentation and are easy to perform. In this study three fluorogenic substrates and their respective fluorophores were studied for the purpose of developing a continuous fluorometric method for GUS. The fluorescence intensity of 6-chloro-4-methyl-umbelliferone (6-CMU) at pH 6.8 was found to be 9.5 times higher than that of 4-methyl umbelliferone (4-MU) and 3.2 times higher than the fluorescence of 7-hydroxycoumarin-3-carboxylic acid (3-CU). Michaelis–Menten kinetic parameters of GUS catalysed hydrolysis of 6-chloro-4-methyl-umbelliferyl-β-D-glucuronide (6-CMUG) were determined experimentally (Km = 0.11 mM, Kcat = 74 s−1, Kcat/Km = 6.93 × 105 s−1 M−1) and compared with the ones found for 4-methyl-umbelliferyl-β-D-glucuronide (4-MUG) (Km = 0.07 mM, Kcat = 92 s−1, Kcat/Km = 1.29 × 106 s−1 M−1) and 3-carboxy-umbelliferyl-β-D-glucuronide (3-CUG) (Km = 0.48 mM, Kcat = 35 s−1, Kcat/Km = 7.40 × 104 s−1 M−1). Finally a continuous fluorometric method based on 6-CMUG as a fluorogenic substrate has been developed for measuring GUS activity. When compared with the highly used discontinuous method based on 4-MUG as a substrate it was found that the new method is more sensitive and reproducible (%RSD = 4.88). Furthermore, the developed method is less laborious, faster and more economical and should provide an improved alternative for GUS assays and kinetic studies.
Co-reporter:Kevin Murphy, Brendan Heery, Timothy Sullivan, Dian Zhang, Lizandra Paludetti, King Tong Lau, Dermot Diamond, Ernane Costa, Noel O׳Connor, Fiona Regan
Talanta 2015 Volume 132() pp:520-527
Publication Date(Web):15 January 2015
DOI:10.1016/j.talanta.2014.09.045
•The design and build of a low-cost optical sensor for water monitoring is described.•The optical detection capabilities are defined and characterised.•Laboratory tests and field deployments undertaken are detailed.•Field deployment carried out alongside a commercial instrument.•The sensors ability to measure opacity and colour changes in water is illustrated.A low-cost optical sensor for monitoring the aquatic environment is presented, with the construction and design described in detail. The autonomous optical sensor is devised to be environmentally robust, easily deployable and simple to operate. It consists of a multi-wavelength light source with two photodiode detectors capable of measuring the transmission and side-scattering of the light in the detector head. This enables the sensor to give qualitative data on the changes in the optical opacity of the water. Laboratory tests to confirm colour and turbidity-related responses are described and the results given. The autonomous sensor underwent field deployments in an estuarine environment, and the results presented here show the sensors capacity to detect changes in opacity and colour relating to potential pollution events. The application of this low-cost optical sensor is in the area of environmental pollution alerts to support a water monitoring programme, where multiple such sensors could be deployed as part of a network.
Co-reporter:Kevin Murphy, Timothy Sullivan, Brendan Heery, Fiona Regan
Sensors and Actuators B: Chemical 2015 214() pp: 211-217
Publication Date(Web):
DOI:10.1016/j.snb.2015.02.023
Co-reporter:Louise Mckeon;Barry Burns;Ray Leonard
Journal of Separation Science 2014 Volume 37( Issue 19) pp:2791-2796
Publication Date(Web):
DOI:10.1002/jssc.201400014
Rosins are used in a wide variety of industries in varnishes, adhesives, drug coatings, etc. In this project a novel capillary electrophoresis method was developed to investigate the resin acid composition of rosins. The acids were separated and the concentrations of individual acids present in gum rosin samples determined in order to investigate any links between the presence and concentration of these acids and the tendency of rosins to crystallize. The capillary electrophoresis method successfully separated nine resin acids in various rosin samples where previously they could not all be separated. Calibration curves were created to determine acid concentration. Abietic, dehydroabietic, neoabietic, pimaric, isopimaric, levopimaric, sandaracopimaric, palustric, and 7-oxo-dehydroabietic acids were separated using a 20 mM tris buffer at pH 9 containing 15% methanol 5 mM (2-hydroxypropyl)-γ-cyclodextrin 10 mM sulfobutylether-β-cyclodextrin. Their concentrations in a crystallizing and a noncrystallizing rosin sample were determined.
Co-reporter:Timothy Sullivan, Ciara Byrne, Luke Harman, John Davenport, Rob McAllen and Fiona Regan
Analytical Methods 2014 vol. 6(Issue 15) pp:5489-5497
Publication Date(Web):16 May 2014
DOI:10.1039/C3AY42162G
Measurement and prediction of ocean acidification effects for nearshore marine ecosystems is currently a major objective of climate change research. This study examines the scales of pH variability in both surface waters (<10 m depth) and deeper waters associated with localised seasonal hypoxia over two years at Lough Hyne marine reserve, Cork, Ireland. Lough Hyne, a semi-enclosed marine system, experiences localised seasonal (approximately May to September each year) hypoxia and eventual anoxia below a depth of circa 25 m, due largely to its bathymetric profile. We report the relationships between pH and other environmental parameters such as dissolved oxygen (DO) and temperature at this location, and we provide data, obtained using continuous autonomous sensing technology, which demonstrates that the variability in pH measurements in the waters of Lough Hyne marine reserve are comparable to predictions of future ocean acidification. This is of interest as comparatively few directly measured time series of pH in marine waters are reported, and additionally the first pH measurements were reported from Lough Hyne over 6 decades ago in 1952. This work also measures for the first time the steep chemical gradients associated with the transition from anoxia to normoxia that result in profound pH changes at Lough Hyne, providing insight into natural variability in pH experienced by marine organisms at such locations.
Co-reporter:James Chapman, Laurianne Le Nor, Robert Brown, Eolann Kitteringham, Sonia Russell, Timothy Sullivan and Fiona Regan
Journal of Materials Chemistry A 2013 vol. 1(Issue 45) pp:6194-6200
Publication Date(Web):15 Oct 2013
DOI:10.1039/C3TB21285H
Copper has been known to possess antimicrobial properties since as far back as the Phoenician era where ship hulls were copper sheathed to prevent the inevitable effects of biofouling. As a consequence of evolving scientific research and development, the realisation of novel materials and agents has enabled new scientific branches – such as nanotechnology. In this paper we investigate the performance of different forms of copper (macro, micro and nano) for application as antifouling materials. Samples are deployed in SmartBay Ireland for four weeks and analysed for evidence of biofouling. It was found that copper in its nano form, produced the greatest antifouling effectiveness in both PDMS and sol–gel matrices.
Co-reporter:James Chapman
Advanced Engineering Materials 2012 Volume 14( Issue 4) pp:B175-B184
Publication Date(Web):
DOI:10.1002/adem.201180037
Abstract
In this work, a novel preparation for superhydrophobic nanofunctionalized silver and gold, copper-coated substrates as potential antifouling coatings for environmental monitoring devices are fabricated. The superhydrophobic coating is topographically similar to the design of the Lotus leaf (Nelumbo necifera) and was synthesized by creating an electroless galvanic reaction between copper and the metal salt. In doing so, a nano- and micro-topographical structure was created on the surface of a copper substrate which can be rendered superhydrophobic through the addition of a self-assembled monolayer (SAM) of CF3(CF2)7CH2CH2SH.
The work investigates whether the hydrophobicity of such materials affects micro-organism attachment and subsequent biofouling. The materials are deployed in a marine environment in Dublin, Ireland for a 6 week study to determine the overall antifouling capacity. The materials are analyzed for biomass, slime (glycocalyx) production and more specifically protein and carbohydrate adsorption all of which are attributed to the inherent makeup of biofilm and exopolymeric substances (EPS) which are secreted by micro-organisms during the biofouling process. This work highlights the dominance of combinational antifouling approaches rather than single tactics for such a complex problem and one that plagues multiple research areas. This novel approach in developing a new antifouling material for sensors, and indeed, any aquatic platform has shown excellent results throughout.
Co-reporter:Shane Bermingham;Robert O'Connor;Gillian P. McMahon
Journal of Separation Science 2010 Volume 33( Issue 11) pp:1571-1579
Publication Date(Web):
DOI:10.1002/jssc.201000026
Abstract
An online SPE-LC method that can determine both anthracyclines and taxanes simultaneously in human serum samples is reported. The entire method of extraction, separation and UV detection was achieved online by column switching between an SPE column (Biotrap 500 (20×4 mm)) and an analytical column (Zorbax XDB C18, 150×4.6 mm, 5 μm) with a 23 min total cycle time. The method is linear (r2>0.998) over the range of 0.5–25 μg/mL. The analytes of interest are retained on the SPE column with good recovery (84–117%), while proteins and other serum components elute to waste. This online clean-up is much faster (150 s) and less manual than traditional off-line extraction methods. Using 0.1 mL spiked serum samples, the LOQ was 0.5 μg/mL. Intra- and inter-day precision were acceptable (≤15% RSD) at and above the LOQ. The method was applied to the analysis of serum samples from patients undergoing chemotherapy with these agents.
Co-reporter:James Chapman, Emma Weir, Fiona Regan
Colloids and Surfaces B: Biointerfaces 2010 Volume 78(Issue 2) pp:208-216
Publication Date(Web):1 July 2010
DOI:10.1016/j.colsurfb.2010.03.002
Biofilms present operational problems to a variety of industrial areas including but not limited to, medicine, water treatment, sensor sensitivity and shipping. Bacterial adhesion resides as a tiny monolayer and builds-up over time with the production of protective slimes known as extracellular polymeric substances (EPS) forming the ‘biofilm’. Infection, inefficiency and diminution of quality are caused by biofilms, which have the potential to be prohibitively expensive to repair.The value of an effective coating that prevents the adhesion of bacteria and subsequent fouling is paramount in preserving sensitivity and longevity of a subjected operational substrate. Polymer and sol–gel (SG) based coatings tender a matrix for the introduction of biocides and antimicrobial agents that offer this prevention. They present a relatively cheap and optically clear platform that can then be doped with the antimicrobial agent. This proves useful in transferring across a range of industries that may require a transparent function to the coating.Nanoparticles offer a means of new line research in combating biofouling and biocorrosion with interest stemming from silver metal nanoparticles (MNPs) that already offer antimicrobial property. The aim of this work is to investigate period four metal nanoparticles for any antimicrobial potential they offer, in the prevention of fouling in the early stages. The research presented herein uses a range of period four MNPs synthesised through an adapted polyol reduction, which have then been doped into SG coatings and tested for their efficacy in preventing levels of biofouling. After a 7-day freshwater study results showed that MNPs prevent levels of biofouling upto 125% compared to the SG blank. The work uses bacterial enumeration, minimum inhibitory concentration (MIC), surface characterisation and slime and biomass analysis to complete a range of studies in assessing the level of fouling observed on the test substrates.
Co-reporter:Keith Farrington, Fiona Regan
Talanta 2009 Volume 78(Issue 3) pp:653-659
Publication Date(Web):15 May 2009
DOI:10.1016/j.talanta.2008.12.013
This paper describes the preparation and testing of a sol gel specific for the non-steroidal anti-inflammatory drug ibuprofen. Ibuprofen was selected as a model compound due to the fact that it contains a number of structural and functional analogues, in this case ketoprofen and naproxen. In order to study the specific criteria affecting selectivity in sol gels, three sol gels were prepared for ibuprofen utilising two and three functional silane systems. The relative rebinding of each of the three compounds to the sol gels was assessed by % recovery in solid phase extraction. The results of the experiments indicate that along with the functionality imparted to the sol gel by the development of template-monomer complexes a major determinant of selectivity is shape selective memory. The utilisation of a three monomer system affords the cavity recognition based on the formation of π–π stacking interactions, hydrogen bonding, van der Waals forces, electrostatic interactions and shape complementarity and minimises cross reactivity. In addition real sample analysis has been performed on urine samples containing ibuprofen and metabolites showing specific preconcentration.
Co-reporter:Emma Weir, Antoin Lawlor, Aine Whelan and Fiona Regan
Analyst 2008 vol. 133(Issue 7) pp:835-845
Publication Date(Web):12 Mar 2008
DOI:10.1039/B715532H
Anti-microbial materials have multiple applications in medicine, industry and commercial products. Recent research has proposed the use of nanoparticles in a range of materials, as some metal nanoparticles are known to possess antibacterial properties. The development of such materials presents both the chemist and the biologist with the challenge to effectively choose analytical methods that provide relevant information regarding these materials. Herein, we describe techniques for the characterization of the nanoparticle-doped materials and methods for the determination of their efficacy against biofilm formation.
Co-reporter:Yuliya Shakalisava
Journal of Separation Science 2008 Volume 31( Issue 6-7) pp:1137-1143
Publication Date(Web):
DOI:10.1002/jssc.200700591
Abstract
This work verifies the potential of CE in the analysis of significant impurities of montelukast sodium – an active ingredient for the treatment of bronchial asthma. Using 20 mM borate buffer pH 9.2 with 10 mM SDS and 10 mM (2-hydroxypropyl)-γ-CD (2HP-γ-CD) it was possible to separate montelukast and several impurities, including its cis-isomer, after exposure to light and oxygen. The obtained method surpasses a chromatographic method for montelukast sodium in terms of time of analysis (9 min of CE analysis vs. 35 min HPLC) and efficiency (CE offered over 900 000 theoretical plates for montelukast). Good repeatability of the method was supported by the low % RSD for the migration time of montelukast (0.53%). For the first time, the capillary electrophoretic method was employed for temporal study of the degradation of montelukast. The results showed that degradation of montelukast and the formation of the cis-isomer mainly occurred during the first 2 days of exposure, and occurred to a higher degree when there was no contact with the air (oxygen) in the exposed sample.
Co-reporter:Gillian Whitaker, Brendan J. Kincaid, Nicole Van Hoof, Fiona Regan, Malcolm R. Smyth, Raymond G. Leonard
International Journal of Adhesion and Adhesives 2007 Volume 27(Issue 7) pp:604-609
Publication Date(Web):October 2007
DOI:10.1016/j.ijadhadh.2006.11.001
In this study, the trace acid profile of cyanoacrylate adhesives was studied using capillary electrophoresis. Liquid–liquid extraction was employed as the sample preparation step before separation by capillary electrophoresis. The solubility of the adhesives was investigated using various organic solvents, e.g. hexane and dichloromethane, and chloroform was determined to be the optimum solvent as it enabled the full dissolution of the adhesive. A comprehensive stability study was performed over a 3-year period and results indicate that the adhesives were stable for 2 years after which their stability and performance degraded.
Co-reporter:Keith Farrington, Edmond Magner, Fiona Regan
Analytica Chimica Acta 2006 Volume 566(Issue 1) pp:60-68
Publication Date(Web):27 April 2006
DOI:10.1016/j.aca.2006.02.057
A rational design approach was taken to the planning and synthesis of a molecularly imprinted polymer capable of extracting caffeine (the template molecule) from a standard solution of caffeine and further from a food sample containing caffeine. Data from NMR titration experiments in conjunction with a molecular modelling approach was used in predicting the relative ratios of template to functional monomer and furthermore determined both the choice of solvent (porogen) and the amount used for the study. In addition the molecular modelling program yielded information regarding the thermodynamic stability of the pre-polymerisation complex. Post-polymerisation analysis of the polymer itself by analysis of the pore size distribution by BET yielded significant information regarding the nature of the size and distribution of the pores within the polymer matrix. Here is proposed a stepwise procedure for the development and testing of a molecularly imprinted polymer using a well-studied compound—caffeine as a model system. It is shown that both the physical characteristics of a molecularly imprinted polymer (MIP) and the analysis of the pre-polymerisation complex can yield vital information, which can predict how well a given MIP will perform.
Co-reporter:Michael McMahon, Fiona Regan, Helen Hughes
Food Chemistry 2006 Volume 97(Issue 3) pp:411-417
Publication Date(Web):August 2006
DOI:10.1016/j.foodchem.2005.05.018
This paper outlines the development of a method for the determination of total germanium in foodstuffs utilising graphite furnace atomic absorption. It was found that by varying the drying times interferences could be minimised. Metals including calcium, cobalt, copper, magnesium, nickel, lead and zinc were tested for potential interferences. It was found experimentally that none of the listed metals interfered with this method. The optimal furnace conditions were determined to be; drying for 80 s (85 °C for 30 s, 95 °C for 40 s and 120 °C for 10 s), ashing at 700 °C for 8 s and atomisation at 2600 °C for 3.3 s followed by a tube clean for 2 s at 2800 °C and a lamp current of 5 mA for analysis at 265.2 nm. The method was found to have a linear range of 3.3–125 μg/l with a limit of detection and a characteristic mass of 0.051 and 0.053 ng germanium, respectively. The samples chosen for analysis include vegetables, fruit juices, Chinese herbal remedies and over the counter formulations. It was found that the aloe vera tablet, ginseng tablet and ginger tablet contained 20.83, 5.48 and 9.96 μg/g. Other foods found to contain germanium were potato, garlic and carrot, having 1.85, 2.79 and 0.60 μg/g of germanium. The food found to contain the highest concentration of germanium was Soya mince having 9.39 μg/g.
Co-reporter:B Fogarty, E Dempsey, F Regan
Journal of Chromatography A 2003 Volume 1014(1–2) pp:129-139
Publication Date(Web):3 October 2003
DOI:10.1016/S0021-9673(03)01039-2
This work examines the potential of microemulsion electrokinetic chromatography for the separation of several priority endocrine disrupting compounds (EDCs). The optimised microemulsion system comprised 25 mM phosphate buffer pH 2, 80 mM octane, 900 mM butanol, 200 mM sodium dodecyl sulphate and was further modified with 20% propanol. The use of a low pH buffer resulted in the suppression of electroosmotic flow within the capillary. Reversal of the conventional electrode polarity resulted in faster migration of hydrophobic compounds. Test analytes included the octylphenol, nonylphenol and nonylphenol diethoxylate, which are breakdown products of the alkylphenolic detergents. The synthetic oestrogens diethylstilbestrol and ethynyloestradiol were also included in the separation along with the plastic monomer bisphenol-A. Test analytes were selected due to their reported presence in environmental samples namely industrial and domestic wastewater treatment effluents and sludges. Using the optimised method a separation of six EDCs was achieved within 15 min. The optimised method was then applied to the analysis of a spiked wastewater influent sample with UV detection of all six compounds at 214 nm.
Co-reporter:Fiona Regan, Anne Moran, Barbara Fogarty, Eithne Dempsey
Journal of Chromatography A 2003 Volume 1014(1–2) pp:141-152
Publication Date(Web):3 October 2003
DOI:10.1016/S0021-9673(03)01036-7
The synthesis and usage of a wide range of organic chemicals has increased dramatically over the last five decades. These compounds sometimes termed endocrine disrupting chemicals include agricultural pesticides, industrial solvents, dyes, plasticisers, detergents and heat exchangers. Concerns have been raised about the potential adverse effects of these compounds on humans and wildlife species. Our objectives are to develop a method to identify, using novel capillary electrophoretic techniques, the endocrine disrupting compounds that are reported to be present in environmental samples. The CE modes, capillary zone electrophoresis, micellar electrokinetic chromatography (MEKC), cyclodextrin-modified MEKC (CD-MEKC) and electroosmotic flow-suppressed CD-MEKC were investigated for the determination of a range of endocrine disrupting chemical compounds. This paper shows some initial results obtained.
Co-reporter:James Chapman, Laurianne Le Nor, Robert Brown, Eolann Kitteringham, Sonia Russell, Timothy Sullivan and Fiona Regan
Journal of Materials Chemistry A 2013 - vol. 1(Issue 45) pp:NaN6200-6200
Publication Date(Web):2013/10/15
DOI:10.1039/C3TB21285H
Copper has been known to possess antimicrobial properties since as far back as the Phoenician era where ship hulls were copper sheathed to prevent the inevitable effects of biofouling. As a consequence of evolving scientific research and development, the realisation of novel materials and agents has enabled new scientific branches – such as nanotechnology. In this paper we investigate the performance of different forms of copper (macro, micro and nano) for application as antifouling materials. Samples are deployed in SmartBay Ireland for four weeks and analysed for evidence of biofouling. It was found that copper in its nano form, produced the greatest antifouling effectiveness in both PDMS and sol–gel matrices.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 15) pp:
Publication Date(Web):
DOI:10.1039/C3AY42162G
Measurement and prediction of ocean acidification effects for nearshore marine ecosystems is currently a major objective of climate change research. This study examines the scales of pH variability in both surface waters (<10 m depth) and deeper waters associated with localised seasonal hypoxia over two years at Lough Hyne marine reserve, Cork, Ireland. Lough Hyne, a semi-enclosed marine system, experiences localised seasonal (approximately May to September each year) hypoxia and eventual anoxia below a depth of circa 25 m, due largely to its bathymetric profile. We report the relationships between pH and other environmental parameters such as dissolved oxygen (DO) and temperature at this location, and we provide data, obtained using continuous autonomous sensing technology, which demonstrates that the variability in pH measurements in the waters of Lough Hyne marine reserve are comparable to predictions of future ocean acidification. This is of interest as comparatively few directly measured time series of pH in marine waters are reported, and additionally the first pH measurements were reported from Lough Hyne over 6 decades ago in 1952. This work also measures for the first time the steep chemical gradients associated with the transition from anoxia to normoxia that result in profound pH changes at Lough Hyne, providing insight into natural variability in pH experienced by marine organisms at such locations.
