Environmental Trace Analysis Research Articles

Simple, fast and inexpensive large “whole water” volume sample SPE-loading using compressed air and finely ground sand

In environmental trace analysis there is often a need to enrich the compounds of interest from a large sample volume, where the use of solid phase extraction (SPE) is more or less the standard technique.

Eco-friendly environmental trace analysis of thorium using a new supramolecular solvent-based liquid-liquid microextraction combined with spectrophotometry

A novel green supramolecular solvent-based liquid-liquid microextraction (SsLLME) method was developed and validated for preconcentration of thorium(IV) in various environmental samples. The presented preconcentration method was based on using 1-decanol/THF as supramolecular solvent phase and quinalizarin as a chelating agent. Thorium(IV)-quinalizarin hydrophobic complex was obtained at pH 6.0, extracted into the supramolecular solvent phase, centrifuged and then the absorbance was measured spectrophotometrically at 590 nm. The impact of some variables on the efficiency of microextraction; pH, amount of quinalizarin, and supramolecular solvent type, ratio and volume, ultrasonication and centrifugation time, sample volume and influence of matrix ions; was optimized. Linearity ranged from 2.0 to 100 μg L−1 with a limit of detection (LOD) of 0.40 μg L−1. The preconcentration factor (PF) was found to be 40. The precision of the method was confirmed with its low RSD% (1.4). The developed method was applied to the analysis of real water and soil samples. The validity was checked with certified reference materials such as IAEA Lake Sediment SL-1 and IAEA-soil-7.

Evaluation and reduction of the analytical uncertainties in GC-MS analysis using a boundary regression model

The uncertainties in analysis of trace environmental pollutants may come from sample matrix and sample pretreatment process. In this study, a boundary model was developed based on the visualized data of mass spectrometry to evaluate the influences from sample matrix and pretreatment process. The factors affecting the pretreatment procedures, such as the solvents, the extraction sorbents and the extraction process had limited influences compared with matrix effects. Using such boundary model, we found that selecting suitable qualitative and quantitative ions for MS detector is more important for reducing the matrix effect in GC-MS analysis than the traditionally used methods of optimizing the pretreatment process since some clean up sorbents might be useless to reduce the matrix effects. As for 2,2′,4,4′,5-pentabromodiphenyl ether (BDE-99), the fragmental ions were usually used for qualitative and quantitative analysis, which however was easily affected by the matrix effects. While, molecular ions would eliminate the influences from the sample matrix. Such a model could be used to decrease the uncertainty and increase the accuracy of environmental trace analysis.

Online solid phase extraction liquid chromatography using bonded zwitterionic stationary phases and tandem mass spectrometry for rapid environmental trace analysis of highly polar hydrophilic compounds – Application for the antiviral drug Zanamivir

Zanamivir (Za) is a highly polar and hydrophilic antiviral drug used for the treatment of influenza A viruses. Za has been detected in rivers of Japan and it's environmental occurrence has the risk of inducing antiviral resistant avian influenza viruses. In this study, a rapid automated online solid phase extraction liquid chromatography method using bonded zwitterionic stationary phases and tandem mass spectrometry (SPE/LC–MS/MS) for trace analysis of Za was developed. Furthermore, an internal standard (IS) calibration method capable of quantifying Za in Milli-Q, surface water, sewage effluent and sewage influent was evaluated. Optimum pre-extraction sample composition was found to be 95/5 v/v acetonitrile/water sample and 1% formic acid. The developed method showed acceptable linearities (r2≥0.994), filtration recovery (≥91%), and intra-day precisions (RSD≤16%), and acceptable and environmentally relevant LOQs (≤20ngL−1). Storage tests showed no significant losses of Za during 20 days and +4/−20°C (≤12%) with the exception of influent samples, which should be kept at −20°C to avoid significant Za losses. The applicability of the method was demonstrated in a study on phototransformation of Za in unfiltered and filtered surface water during 28 days of artificial UV irradiation exposure. No significant (≤12%) phototransformation was found in surface water after 28 days suggesting a relatively high photostability of Za and that Za should be of environmental concern.

DETERMINATION OF UV-FILTER COMPOUNDS IN HIGHLY CONTAMINATED RIVER WATER BY HPLC-DAD: A COMPARATIVE STUDY ON EXTRACTION EFFICIENCY AND APPLICABILITY OF DIFFERENT SOLID PHASE EXTRACTION SORBENTS

UV-filter compounds, which are mostly formulated in cosmetic and hygienic products, are known as an emerging group of environmental pollutants. Solid phase extraction using silica based sorbents followed by high performance liquid chromatography has been the most frequently used technique for extraction and analysis of these analytes in the products formulations as well as environmental samples. In this work, the mentioned sorbent (LiChrolut RP-18) has been compared with commercially available polystyrene-divinylbenzene (LiChrolut EN) and LiChrolut RP-18 + LiChrolut EN cartridges. Efficiency of the sorbents for extraction of Benzophenone-3, 4-methylbenzilidene camphor, octocrylene, and Ethylhexyl methoxy cinnamate, as the representatives of UV-filter compounds at neutral and acidic sample solutions, has been studied. Comparing relative recoveries of extraction showed that LiChrolut EN was significantly more efficient for the extraction from the contaminated matrix of river water, especially for more polar components, although no gross difference was observed in the case of spiked pure solutions. The chosen approach for the analysis showed LODs from 0.2 to 0.6 µgL−1, and linear responses from 0.5 to 100 µ g L−1. The reproducibility of the method (RSD from 1.4 to 10.4% at 5 µgL−1) was sufficient for precise environmental trace analysis.

RECENT HPLC STRATEGIES TO IMPROVE SENSITIVITY AND SELECTIVITY FOR THE ANALYSIS OF COMPLEX MATRICES

Recently, various approaches have been addressed to improve chromatographic performance in terms of sensitivity or selectivity, from the development of novel on-line (or off-line) enrichment methodologies, to the improvement of stationary-phase type and multidimensional chromatography, to novel and more performing detectors such as tandem mass spectrometry (MS/MS), nuclear magnetic resonance (NMR), and infrared spectrometry (IR). For the analysis of complex matrices (e.g., biological fluids, plant extracts, food, and environmental samples), coupling chromatographic instrumentation with these detectors provides a powerful analytical device that can be applied in many fields, such as analysis of pharmaceutical and natural products (and medicinal plant), quality control, and environmental trace analysis. This review describes major advances in the HPLC field in terms of enrichment techniques and chromatographic separation, and especially in terms of detector improvement for a complete identification and quantification of targeted analytes. The possibility of high-throughputs analyses, as a consequence of sensitivity and selectivity enhancement in drug and metabolites profile and multi-residue assays for natural compounds and/or products containing natural species, is also highlighted. Finally, it is shown how multivariate analysis may enhance analytical performance in terms of useful analytical information that can be extracted from experimental data and in terms of methods for exploring and modeling data. Chemometrics provides tools for making the most of analytical signals, once selectivity and sensitivity have been improved from the chemical point of view.

Speciation of gadolinium based MRI contrast agents in environmental water samples using hydrophilic interaction chromatography hyphenated with inductively coupled plasma mass spectrometry

A highly sensitive method for the determination of gadolinium based MRI contrast agents in environmental water samples has been developed using hydrophilic interaction chromatography (HILIC) coupled with inductively coupled plasma mass spectrometry (ICP-MS). The contrast agents used in the present study are Gd-DTPA (Magnevist), Gd-DTPA-BMA (Omniscan), Gd-DOTA (Dotarem), Gd-BOPTA (Multihance) and Gd-BT-DO3A (Gadovist) which represent both classes of linear and macro cyclic and also ionic and non ionic contrast agents. A study of various parameters responsible for the efficient separation was performed and resulted in an optimum mobile phase composition of 20 mmol L−1 ammonium acetate in 60/40 ACN/water mixture at a flow rate of 0.1 mL min−1 in combination with a micro concentric type PFA nebuliser and ICP-MS detection of the 158Gd isotope. All contrast agents have shown excellent linearity between 0.1 μg L−1 and 100 μg L−1 (R2 > 0.99) for each MRI contrast agent with RSD values found to be less than 2% for triplicate measurements. The limit of quantification (LOQ) for all contrast agents were found to be less than 100 ng L−1 which allows the developed method to be employed in environmental trace analysis. Enrichment of water samples for the determination of contrast agents was performed by using a surface evaporation approach. The developed method has been applied successfully for the separation and determination of contrast agents in surface and waste water treatment plant samples. The MRI agent speciation results were compared with ICP-MS measurements for the total Gd concentrations.

Determination of triazines and their metabolites in environmental samples using molecularly imprinted polymer extraction, pressurized liquid extraction and LC–tandem mass spectrometry

Summary The present work describes the development of a selective and sensitive method for the simultaneous determination of triazines and triazine metabolites in waters and soils, and its further application to natural samples. The method is based on sample extraction and pre-concentration with commercial molecularly imprinted polymer cartridges (MIP4SPE Triazine 10) followed by liquid chromatography–tandem mass spectrometric (LC–MS/MS) analysis operating in the selected reaction monitoring (SRM) mode. Method detection limits achieved were as low as 0.015 ng L −1 (ground water) and 0.2 ng kg −1 (soil and sludge). Method recovery rates were found to be analyte dependent, ranging from 55% to 123%. The intra-day and inter-day precision was given by RSD values between 2% and 4% and between 6% and 10%, respectively for the latter for most compounds. The suitability of the method for the environmental trace analysis of triazine pesticides and their metabolites in aqueous samples was demonstrated through the analysis of several ground water and sludge-amended soil samples. The outcomes of this study revealed that simazine was the most frequently found analyte in ground water, with values up to 105.11 ng L −1 . Results also evidenced that all the pesticides investigated were present in the solid matrices, being sebuthylazine that at the highest concentrations, with values ranging from 0.46 to 2.26 ng g −1 . Pesticide concentrations in the sludge applied as fertilized were generally low, which indicated that their contribution to the total amount of pesticides in the soil was not quantitatively relevant in comparison with that of pesticides coming from direct spreading to agricultural lands.

ENEA Activities in the Field of Laser Spectroscopic Techniques for Environmental Trace Analysis with Perspectives of Applications to Nuclear Safeguards

The ENEA (Italian National Agency for New Technologies, Energy and the Environment) laser spectroscopic activities carried on at the Laser Application Section of the Frascati Research Center are presented with main emphasis given to the additional capabilities of environmental monitoring of hidden nuclear activities or possible nuclear disasters. High resolution linear spectroscopies based on photo-acoustic or multipass detection techniques, together with nonlinear in-situ and remote sensing stand-off instruments are reviewed. The current results have been presented upon invitation at the IAEA Safeguards Technical Meeting [1].

Modern Potentiometry

For most chemists, potentiometry with ion-selective electrodes (ISEs) primarily means pH measurements with a glass electrode. Those interested in clinical analysis might know that ISEs, routinely used for the determination of blood electrolytes, have a market size comparable to that of glass electrodes. It is even less well known that potentiometry went through a silent revolution during the past decade. The lower detection limit and the discrimination of interfering ions (the selectivity coefficients) have been improved in many cases by factors up to 10(6) and 10(10), respectively, thus allowing their application in fields such as environmental trace analysis and potentiometric biosensing. The determination of complex formation constants for lipophilic hosts and ionic guests is also covered in this Minireview.

On the occasion of Professor Werner Engewald’s 70th birthday

In this issue of Analytical and Bioanalytical Chemistry you will find a tribute to Professor Emeritus Werner Engewald on the occasion of his 70th birthday. I got to know Werner Engewald when I was a student at the University of Leipzig attending my first lectures on separation science. He has been a mentor and advisor ever since and it is my great honor and pleasure to start this issue with a few reflections on his work and vitae. Werner was born in Glauchau, a small town in Saxony, Germany, in August 1937. He studied chemistry at the University of Leipzig from 1957 to 1962 and obtained his Ph.D. in 1968. In the same year, he attended an international symposium on chromatography in Berlin, and I believe it was back then that he discovered his passion for the separation sciences. After postdoctoral studies in 1971 under A.V. Kislev at the Moscow State University he returned to Leipzig and obtained his habilitation in 1978. In 1979 he was appointed assistant professor in analytical chemistry, and later became a full professor. His scientific interests cover a broad range, including structure–retention relationships in gas chromatography, chromatographic multicomponent analysis, environmental trace analysis, and various sample preparation techniques. He is also interested in hyphenated techniques, such as GC–MS and GC–AED, adsorptive enrichment in combination with thermal desorption, pyrolysis GC, and more recently LC–MS techniques. Werner has mentored more than 35 Ph.D. students, and he is still in contact with many of them. He has published over 200 articles, reviews, and book chapters. Besides the challenging task of running a research group, Werner has always set time aside for professional activities such as serving as departmental head. Werner is also an active member of the separation science working group in the analytical chemistry division of the German Chemical Society; he has served as chairman of the working group and is still a board member of the analytical chemistry division of the German Chemical Society. Over the years he has participated on the editorial boards of several journals, including Fresenius’ Journal of Analytical Chemistry, and reviewed countless manuscripts. In cooperation with the German Chemical Society, he has organized many well-known training courses in gas Anal Bioanal Chem (2007) 388:1631–1632 DOI 10.1007/s00216-007-1380-2

Improved liquid chromatographic determination of nine currently used (fluoro)quinolones with fluorescence and mass spectrometric detection for environmental samples

An HPLC method using C18-modified silica as stationary phase has been developed for environmental trace analysis of nine (fluoro)quinolones. Detection is done by fluorescence measurement or MS using the modes of SIM and selected reaction monitoring (SRM). Best separation is achieved with a gradient consisting of 50 mM formic acid and methanol, which is fully compatible with MS coupling. LOQs (S/N of 10) for fluorescence detection are between 10 and 60 microg/L, depending on the analyte. MS detection (SIM and SRM) yields LOQs that are better by a factor of at least an order of magnitude. Sample preconcentration and sample clean-up is accomplished by SPE (preconcentration factor of 1000), leading to LOQs in the low ng/L range. Recoveries of the preconcentration procedure are better than 80% for all analytes. The suitability for real samples has been demonstrated by analyzing surface waters, municipal waste waters, sewage treatment plant effluents, sewage sludge, and sediment taken from rivers and fish ponds. The method should also be useful for determination of residues of (fluoro)quinolones in food or other matrices. The degradation of the (fluoro)quinolones has been examined over 5 days in order to get information about the decomposition rate and the degradation products eventually occurring in the environment.

Determination of Environmentally Relevant Compounds Using Fast GC/TOF-MS

The use of GC/MS techniques is crucial to modern environmental trace analysis. However, due to the slow scanning capabilities of common quadrupole detectors, the implementation of fast gas chromatography is restricted. The now evolving Time-of-Flight mass detectors, have fast scanning capabilities and thus can provide the data density necessary to accurately define narrow chromatographic peaks typical for accelerated GC methods.The applications described herein demonstrate how the analysis of acidic pesticides and acidic drugs can be easily accelerated by a factor of 5 to 10 simply by using smaller column dimensions and higher helium flow rates. The quantitative data recorded with a Leco Pegasus II TOF system were comparable to the results obtained with the original routine methods. In addition to the fast acquisition, special software features allow peaks to be found automatically even when they are buried underneath the baseline, thus enabling an additional screening for unknown components besides the target analysis. A spectral deconvolution algorithm separates overlapping mass spectra and thus helps to deal with coeluting signals which can often be observed using fast GC conditions.

Laser mass spectrometry for environmental and industrial chemical trace analysis

Laser mass spectrometry for environmental and industrial chemical trace analysis

Improvements in environmental trace analysis by GC-IR and LC-IR

Research has been carried out to enlarge the potential of infrared (IR) spectrometry as a detector in gas and liquid chromatography (GC and LC). The study has been directed to applications in environmental analysis. Examples of recently obtained results are presented. The analyte detectability of GC-IR has been improved by incorporation of an on-column interface for the introduction of large sample volumes. The feasibility of the technique is demonstrated by the identification of pesticides in water at a level of 0.5 μg 1 −1 using on-line desorption of pre-sampled solid-phase extracted cartridges. The detectability of LC-IR, based on solvent elimination interfacing, has been enhanced by on-line trace enrichment. The applicability has been extended to buffered aqueous mobile phases by on-line post-column liquid-liquid extraction into a volatile solvent, and to gradient separations by reduction of the analytical flow using capillary LC combined with post-column addition of a make-up liquid. With both techniques, herbicides have been identified in water samples in the low μg 1 −1 range.

Automated gas chromatographic analysis of volatile organic compounds in air

The performance of an automated system developed for environmental trace analysis to collect, preconcentrate and analyse organic atmospheric pollutants present in the ppb and ppt range was evaluated by taking into account the use of several detectors for identification. Organic compounds present in air, directly taken from the atmosphere or carried to the laboratory in passivated canisters or bags, were sampled with a large volume loop, concentrated in a trap filled with different types of adsorbents, thermally desorbed and stripped by a stream of pure gas and analysed with capillary columns of different length, diameter and polarity. A programmed temperature vaporization injector (PTV) was also used for refocusing of the sample before analysis. Flame ionization and photoionization detectors were used for the determination of aromatic and aliphatic compounds. The sensitivity and stability of the system were checked. Some examples of application to the analysis of different samples at various concentrations are described.

The use of supercritical-fluid extraction in environmental analysis

Different applications of supercritical-fluid extractions (SFE) in the field of environmental trace analysis are presented. A simple method for quantitative trapping of extracted compounds in off-line SFE is described in detail. With this device, compounds with a boiling point higher than 120°C could be trapped with recoveries of over 90% compared with external standard. Recovery studies of chlorinated pesticides (Lindane and pp'-DDT) and poly-chlorinated biphenyls (PCB's) in soil were performed at low ppb levels. On-line SFE-GC was used to measure the recoveries of PCB's from the adsorbents Tenax, Carbopack C, Spherosil XOA 200, Florisil and reversed phase C18 sorbent. It was shown that the adsorbents gave satisfactory blanks with SFE cleaning. Ten-minute extractions yielded quantitative recoveries (500 pg) of the PCB's. Carbopack cannot be used under supercritical conditions due to the instability of the material. High molecular artefacts were observed, when large volume of air was enriched on Tenax. A low volume sampling/SFE-unit for the analysis of aerosol particles is presented and aspects of fractionation of particulate organic matter and selective extraction of PAH's by stepwise SFE are discussed.

Why do we need more powerful methods in environmental trace analysis of the elements and what scope exists?

In view of the increasing tasks involved and the ultimately arising limits of trace-, micro distribution- and species analysis of the elements, the present state and an outlook onto more sensitive and reliable analytical methods are critically discussed

Texanol Isobutyrate and Other Additive Chemicals-Environmental Contaminants or Laboratory Artifacts?

Abstract Over a period of years, trace organic analysis of Scottish river water and fish samples using gas-chromatography/mass-spectrometry (GC-MS) has often shown the presence of a component with similar elution properties to diethylphthalate and with a dominant ion in the mass spectrum at m/z 71. Closer investigation of this material has now shown it to be 2,2,4-trimethyl-1,3-pentandiol diisobutyrate (common name Texanol isobutyrate), a widely-used industrial chemical marketed as Kodaflex TXIB with applications as a plasticiser, cross-linking agent and lubriciant. The origin of TXIB in analytical samples has been traced to contamination during solvent evaporation operations and it is suggested that a possible source of the chemical might be by slow release into the laboratory atmosphere from vinyl floor coverings. A summary is given of other common contaminants which were identified in the course of these investigations. The genuine occurrence of such materials in environmental samples is not ruled out but these findings highlight the need for rigorous quality assurance in environmental trace analysis if reported levels are to be truly meaningful. A brief assessment of the environmental significance of TXIB is provided.

Improving the quality of environmental trace analysis

Improving the quality of environmental trace analysis