In this article, a dataset from a collaborative non-target screening trial organized by the NORMAN Association is used to review the state-of-the-art and discuss future perspectives of non-target screening using high resolution mass spectrometry in water analysis. A total of 18 institutes from 12 European countries analysed an extract of the same water sample collected from the River Danube with either one or both of liquid and gas chromatography coupled with mass spectrometric detection. This article focuses mainly on the use of high resolution screening techniques with target, suspect and non-target workflows to identify substances in environmental samples. Specific examples are given to highlight major challenges such as isobaric and co-eluting substances, dependence on target and suspect lists, formula assignment, the use of retention information and the confidence of identification. Approaches and methods applicable to unit resolution data are also discussed. While most substances were identified using high resolution data with target and suspect screening approaches, some participants proposed tentative non-target identifications. This comprehensive dataset revealed that non-target analytical techniques are already considerably harmonized between the participants, but the data processing remains time-consuming. Although the dream of a "fully-automated identification workflow" remains elusive in the short-term, important steps in this direction have been taken, exemplified in the growing popularity of suspect screening approaches. Major recommendations to improve non-target screening include better integration and connection of desired features into software packages, the exchange of target and suspect lists and the contribution of more spectra from standard substances into (openly accessible) databases.
An innovative analytical method has been developed for the determination of glyphosate and aminomethylphosphonic acid (AMPA), its major metabolite, in sewage sludge. This method involved an alkaline extraction from sludge and purification on a strong anion-exchange resin. While the analytes remained fixed by ionic interactions, an "on-solid support" derivatization by FMOC-Cl was carried out. This versatile approach allowed a 10 min reaction and simple elimination of the excess of reagent. The resulting derivatives remained retained by ionic and hydrophobic interactions with the resin until being eluted by a mixed NaCl water/acetonitrile, 70/30, v/v, solution. After an appropriate dilution and adjustment of the pH, the sample was concentrated on an Oasis HLB solid-phase cartridge. For quality analysis of traces in complex matrixes, LC-ESI-MS/MS in the multiple reaction monitoring positive mode was used fulfilling the European Union requirements (Decision 2002/657/CE). To overcome the matrix effects, stable isotopically labeled standards were added to the sludge extracts as internal standards and were thus derivatized during the procedure in parallel to the analytes. Mean recovery values were 70% +/- 7% for glyphosate and 63% +/- 3% for AMPA. Limits of detection (20 and 30 ppb dw) and limits of quantification (35 and 50 ppb dw) for glyphosate and AMPA, respectively, were sufficient to monitor samples taken from Ile-de-France wastewater treatment plants where contamination currently reached 0.1-3 ppm and 2-35 ppm dw for glyphosate and AMPA, respectively.
Wastewater treatment plants (WWTP) are known to be a source of surface water contamination by organic compounds such as pharmaceuticals. The objective of the present work was to study the suitability of the polar organic chemical integrative sampler (POCIS) to monitor beta-blockers and hormones in effluents and surface waters. Four sampling campaigns were carried out in French rivers (the Saône, the Ardières, the Bourbre, and the Seine) between November 2007 and September 2008. Passive samplers were exposed in surface waters, upstream and downstream of WWTP outflows, and in effluents. Exposures lasted for up to 24 d to study the uptake kinetics directly in situ, and repeatability was assessed by exposure of triplicates. A good agreement was found between POCIS and water samples. With the exception of atenolol, beta-blockers showed a linear uptake during at least three weeks, and their sampling rates could be determined in situ. These sampling rates were then used to calculate time-weighted average concentrations of beta-blockers in the Seine River with an overall good accuracy and repeatability. Such calculations could not be performed for hormones because of their variable occurrences and low concentrations in water and POCIS. Polar organic chemical integrative sampler therefore seems to be a suitable tool for monitoring beta-blockers in surface waters impacted by WWTP effluents. Longer exposure durations would be necessary to determine the suitability of POCIS for monitoring hormones. Finally, preliminary assays on the use of several deuterated compounds as performance reference compounds showed promising results for deuterated atenolol.
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