Robert Baudot

Multi-residue analysis of steroids at sub-ng/L levels in surface and ground-waters using liquid chromatography coupled to tandem mass spectrometry

Most analytical methodologies currently available for the determination of steroids in water only identify a few representative compounds (mainly estrogens). In this context, a multi-residue methodology based on liquid chromatography-tandem mass spectrometry was developed for the determination of 26 steroids including natural and synthetic estrogens, progestagens and androgens. The method described involves limited sample preparation as it includes a filtration followed by a single solid-phase extraction step using a C18 cartridge. The analytical procedure allows the determination of the target analytes in the lower ng/L range, with recoveries above 80%. The methodology was successfully applied to the analysis of steroids in several surface and ground-waters. In all the waters, estrogens, androgens and/or progestagens were determined.

Multi-residue analysis and ultra-trace quantification of 36 priority substances from the European Water Framework Directive by GC-MS and LC-FLD-MS/MS in surface waters.

A multi residue analysis was developed for screening, quantification and confirmation of 36 priority organic compounds included in the 2000/60/EC European Water Framework Directive. The compounds analyzed included 19 pesticides, 8 PAH, 5 endocrine-disruptors and 4 organochlorine compounds. The method was developed in three steps. First, automated off-line solid-phase extraction using Strata X cartridges was optimized to trap simultaneously the 36 studied compounds. Second, the more volatile compounds were analysed by gas chromatography coupled to mass spectrometry with electron impact ionisation in selected ion monitoring mode (SIM). Third, the last 20 compounds were detected and quantified, in one run, by liquid chromatography coupled to fluorescence detector and tandem mass spectrometry. The excellent selectivity and sensitivity allowed us satisfactory quantification and confirmation at levels as low as 0.2-67 ng L(-1) with recoveries between 59 and 105%. Such methodology was then applied to French surface waters: all the waters present organic contaminants, and their concentration varied according to the origin and nature of substances.

Multiresidue method for the determination of 13 pesticides in three environmental matrices: water, sediments and fish muscle.

Pesticides residues in aquatic ecosystems are an environmental concern which requires efficient analytical methods. In this study, we proposed a generic method for the quantification of 13 pesticides (azoxystrobin, clomazone, diflufenican, dimethachlor, carbendazim, iprodion, isoproturon, mesosulfuron-methyl, metazachlor, napropamid, quizalofop and thifensulfuron-methyl) in three environmental matrices. Pesticides from water were extracted using a solid phase extraction system and a single solid-liquid extraction method was optimized for sediment and fish muscle, followed by a unique analysis by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Limits of quantification were below 5 ng L(-1) for water (except for fluroxypyr and iprodion) and ranged between 0.1 ng g(-1) and 57.7 ng g(-1) for sediments and regarding fish, were below 1 ng g(-1) for 8 molecules and were determined between 5 and 49 ng g(-1) for the 5 other compounds. This method was finally used as a new routine practice for environmental research.

Optimisation of pressurised liquid extraction for the ultra-trace quantification of 20 priority substances from the European Water Framework Directive in atmospheric particles by GC–MS and LC–FLD–MS/MS

Atmospheric deposition plays an important role in environmental pollution and human health. However, very few information is available on the presence, in atmospheric particles, of organic priority substances in contrast to inorganic fraction. A method for the extraction and quantification of 20 priority organic substances listed in the European Water Framework Directive in atmospheric particles was developed. This method consists in a combination of gas chromatography coupled with mass spectrometry and ultra-high-pressure liquid chromatography coupled with tandem mass spectrometry and fluorescence. Optimized pressurized liquid extraction using a hexane/dichloromethane/isopropanol mixture was used as extraction procedure from atmospheric particulate matter. The influence of several extraction experimental factors related to the PLE was investigated. The optimized extraction method (80°C, 40 bar, 10 min, 1 cycle) exhibited average recoveries of target analytes higher than 62%. The method detection limits (MDL) were between 0.3 ng g(-1) and 83 ng g(-1). This extraction method, combined with sensitive analytical techniques, leads to satisfactory reliability, sensitivity, and accuracy. The method was applied to real samples, collected from two urban sites by an atmospheric sampling prototype developed in this study. The first results reveal a systematic presence of PAHs at high levels (ranging from 500 ng g(-1) to 10 μg g(-1)) and a variable and lower presence of pesticides at concentrations below 50 ng g(-1) in the samples.

Comparison of Two Analytical Methods for the Determination of Traces of Veterinary Antibiotics and Steroid Hormones in Soil Based on Pressurised Liquid Extraction (PLE) and Quick, Easy, Cheap, Effective, Rugged, Safe (Modified-Quechers) Extraction

Veterinary antibiotics and steroid hormones can be present at low levels in soil. Analytical methodologies are therefore necessary to analyse these compounds at the trace level in such a complex matrix. The goal of this work was to compare Pressurised Liquid Extraction (PLE), which is usually used to extract drugs from soil, and a modified-QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method. Furthermore, several clean-up methods were evaluated. Selective Pressurised Liquid Extraction (SPLE) and Dispersive Solid Phase Extraction (dSPE) used after PLE and QuEChERS, respectively, were tested. These techniques permit a fast and simple purification step. SPE, which is frequently used, was also evaluated. To perform this comparison, both recoveries and matrix effects were compared and the analyses were performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). SPLE and dSPE did not significantly decrease matrix effects. A tandem SPE using SAX and Strata-X cartridges offered the best efficiency. Regarding the comparison between PLE and QuEChERS, the modified-QuEChERS led to better recoveries for certain substances. No significant differences were noted in term of matrix effects. Therefore, the modified-QuEChERS method is recommended.

Priority substances in accumulated sediments in a stormwater detention basin from an industrial area

One of the most adopted solutions in developed countries to manage stormwater is detention/retention basins which generate large quantities of sediments that have to be removed regularly. In order to manage them properly, accurate data are needed about their physical and chemical characteristics, particularly on micropollutant concentrations and their associated risk. This work consisted in a two-year sampling of dry sediments from a detention-settling basin. Priority substances, including pesticides, polybrominated diphenyl ethers (PBDE), alkylphenols and bisphenol A (BPA), were monitored. Different sites in the basin bottom were sampled in order to investigate spatial distribution of the contamination. Results show that the increase of the sediment thickness in the basin was heterogeneous with a maximum of 15 cm after two years. Pesticides and PBDE were, if detected, mainly found in low concentrations from 2 ng/g to 286 ng/g. Conversely, alkylphenols and bisphenol A were always quantified at concentrations varying from 6 ng/g to 3400 ng/g. These high levels suggest that these sediments should be managed with precautions. Spatial heterogeneity of alkylphenol ethoxylates and BPA concentrations was observed, with higher contamination of alkylphenol ethoxylates in anaerobic zones and BPA levels correlated with total organic carbon and in a lesser extent to fine particles.