Trace analysis in complex media
The knowledge of our team resides in the development of analytical methods based mainly on gas chromatography (GC), liquid chromatography (HPLC) hyphenated to various mass spectrometry techniques such as simple quadrupole, triple quadrupole, and Q-Tof-HRMS, and capillary electrophoresis followed with fluorescence detection (CE-LIF). These techniques allow the analyses of pesticides, herbicides and drug traces, such as chlordecone, sulfonylureas, glyphosate, diclofenac and the quantification of their degradation products in complex media such as soils, surface and ground waters and rivers. The best parameters to set in place are thus determined to monitor the efficient degradation of the compounds of interest, and to comprehend the mechanisms that occur in the degradation process in order to control and optimize these treatments.
The interest of the capacitively coupled contactless conductivity detector (C4D) has been also demonstrated in capillary electrophoresis (CE) for the quantification of ion traces (few µg/L) in biological fluids and in active ingredients in pharmaceutical drugs.
The usage of pre-concentration techniques such as solid phase micro-extraction (SPME), mostly in situ in plants allows the monitoring of volatile molecules acting as elicitors following an abiotic stress. Headspace SPME-GC-MS allows the identification and the quantification of trace molecules and also a better understanding of the mechanisms that trigger defence responses in plants targeting a bio-aggressor or abiotic stresses.
Researches are undergoing on molecular imprinted polymer (MIP) as sorbent for solid phase extraction (SPE); several molecular imprinted polymers of bioactive molecules such as alkaloids, antitumors and antibiotics are synthetized and used to extract them from complex sample such as plant extracts, plasma, and urine. Following a selective pre-concentration step on a MIP SPE cartridge, detection of traces of neurotransmitters in biological fluids and pesticides in ground waters is performed using CE. Use of MIPs as stationary phase in passive samplers or electrochemical sensors to trap and monitor new families of pollutants in surface waters is studied.