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International audience; Identifying organic contaminants present in aquatic environments is of major concern for water quality monitoring. New analytical and data treatment tools have been developed to meet this challenge. The sample preparation before analyses is the first crucial step to be optimized before using suspect and non-target-screening approaches for qualitative evaluations of water pollution by contaminants from various chemical and usage families. As part of the action of Aquaref, which is the French reference laboratory for environmental monitoring in the Water Framework Directive, different solid phase extraction conditions (SPE, n=3 per condition) were tested towards UHPLC-HRMS (separation by UHPLC carried out with a C18) analysis. The SPE protocols varied according to the extraction phase (Oasis HLB or multilayer cartridge), the elution solvent (methanol or methanol and dichloromethane) and sample pH (pH 3 or 7). To ensure data quality, blank solvents, extracted blanks and quality control (QC) were also injected. The QC sample corresponds to a pool of 5 µL of each sample extract and is injected repeatedly throughout the injection sequence to monitor the analytical repeatability. By suspect screening strategy, most of the investigated compounds were found in all SPE extracts. The results revealed the presence of contaminants such as pesticides, pharmaceuticals, sweeteners, or anti-corrosive agents. For pesticides, approved (e.g. diuron) and not approved (e.g. terbutryn) compounds were both detected. Concerning the pharmaceuticals, drugs acting on the nervous system were most common (e.g. oxazepam), as well as betablockers (e.g. metoprolol). The without any a priori non-target approach highlighted that the SPE conditions affect the quality and the interpretation of the data. The number of signals (features) detected by each method varies, as does the number of signals associated with background noise, for each sample preparation method tested. These results support the suspect screening results. Data treatment revealed that the two SPE with Oasis HLB extraction phase at pH 7 (elution with methanol or methanol and dichloromethane) lead to detection of more signals with m/z above 600 Da. Based on the retention time distribution of signals detected for each SPE methods, the multilayered cartridge allowed the extraction of more polar compounds than the other SPE methods. The comparison of all the signals detected with each SPE condition revealed that 31% to 57% of them are specific to only one SPE method. The evaluation of sample preparation methods prior to suspect and non-target screening is required before data treatment to assess the presence of contaminants in water.

International audience; Identifying organic contaminants present in aquatic environments is of major concern for water quality monitoring. New analytical and data treatment tools have been developed to meet this challenge. The sample preparation before analyses is the first crucial step to be optimized before using suspect and non-target-screening approaches for qualitative evaluations of water pollution by contaminants from various chemical and usage families. As part of the action of Aquaref, which is the French reference laboratory for environmental monitoring in the Water Framework Directive, different solid phase extraction conditions (SPE, n=3 per condition) were tested towards UHPLC-HRMS (separation by UHPLC carried out with a C18) analysis. The SPE protocols varied according to the extraction phase (Oasis HLB or multilayer cartridge), the elution solvent (methanol or methanol and dichloromethane) and sample pH (pH 3 or 7). To ensure data quality, blank solvents, extracted blanks and quality control (QC) were also injected. The QC sample corresponds to a pool of 5 µL of each sample extract and is injected repeatedly throughout the injection sequence to monitor the analytical repeatability. By suspect screening strategy, most of the investigated compounds were found in all SPE extracts. The results revealed the presence of contaminants such as pesticides, pharmaceuticals, sweeteners, or anti-corrosive agents. For pesticides, approved (e.g. diuron) and not approved (e.g. terbutryn) compounds were both detected. Concerning the pharmaceuticals, drugs acting on the nervous system were most common (e.g. oxazepam), as well as betablockers (e.g. metoprolol). The without any a priori non-target approach highlighted that the SPE conditions affect the quality and the interpretation of the data. The number of signals (features) detected by each method varies, as does the number of signals associated with background noise, for each sample preparation method tested. These results support the suspect screening results. Data treatment revealed that the two SPE with Oasis HLB extraction phase at pH 7 (elution with methanol or methanol and dichloromethane) lead to detection of more signals with m/z above 600 Da. Based on the retention time distribution of signals detected for each SPE methods, the multilayered cartridge allowed the extraction of more polar compounds than the other SPE methods. The comparison of all the signals detected with each SPE condition revealed that 31% to 57% of them are specific to only one SPE method. The evaluation of sample preparation methods prior to suspect and non-target screening is required before data treatment to assess the presence of contaminants in water.