Determination of nerve agent biomarkers in human urine by a natural hydrophobic deep eutectic solvent-parallel artificial liquid membrane extraction technique.

Alkyl methyl phosphonic acids (AMPAs) are the major metabolites of organophosphorus nerve agents. A method based on the use of natural hydrophobic deep eutectic solvents as supported liquid membrane in parallel artificial liquid microextraction (PALME) combined with LC-MS/MS analysis was developed and applied to their extraction from urine samples. PALME is a miniaturized liquid-phase extraction method performed in a multiwell plate format where the aqueous sample and the aqueous acceptor phase are separated by a flat membrane impregnated with an organic solvent. In this study, we investigated the possibility of replacing the harmful conventional organic solvent by an emerging green solvent, a coumarin/thymol-based deep eutectic solvent, in ordered to raise the greenness of the sample preparation method. Linear response was obtained in an interval of 0.5, 5 or 10-100 ng/ml depending on the AMPAs with a determination coefficients (R2s) ranging from 0.9751 to 0.9989 for their determination in not treated urine samples. Enrichment factors (EFs) up to 12.65 were obtained, and repeatability was within 8.90-16.28% RSD (n = 12). The limit of quantifications (LOQs: S/N ≥ 10) of the whole analytical procedure were in the range from 0.04 to 5.35 ng/ml. In addition to its good sensitivity, the presented method permitted the treatment of 192 samples in 120 min (equivalent to 37.5 s/sample), which places it as one of the most powerful preparation technique for biomonitoring of civilian or military people exposed to nerve agents in case of public health emergency. Indeed, the developed procedure combined sensitivity, high-throughput, greenness, simplicity and practicality for the determination of five acidic polar AMPAs in urine samples.

Parallel artificial liquid membrane extraction of organophosphorus nerve agent degradation products from environmental samples.

An emerging miniaturized high-throughput microextraction technique named Parallel artificial liquid membrane extraction (PALME) was, for the first time, investigated for the extraction of polar alkyl methylphosphonic acids (AMPAs) that are the degradation products of organophosphorus nerve agents. The effect of the key-parameters of the extraction method (nature of the membrane, of the extraction solvent, of the pH values of both donor and acceptor phases, agitation speed, extraction time, temperature and ionic strength) on the extraction recoveries was studied in spiked pure water samples. This led to extraction recoveries in the range of 25-102% for the 5 targeted analytes from water with enrichment factors in the range of 4.50-42.75. The developed PALME-LC-MS/MS method was first evaluated with spiked pure water. LOQs (S/N ≥ 10) were in the range of 0.009-1.141 ng mL-1, linearity above 0.9973 for all the AMPAs and with RSD values below 11%. This method was then applied on simulated waste water, river water and aqueous soil extracts. The achieved LOQs were in the range of 0.011-1.210, 0.013-1.196 and 0.016-6.810 ng mL-1, respectively. A detailed comparison of the performances of this PALME method with those of a previously developed hollow fiber liquid-phase microextraction methods already applied to AMPAs was done thus allowing to demonstrate the easy transfer of methods from HF-LPME to PALME. Moreover, the high-throughput potential of PALME was revealed since 192 samples were processed in parallel during 120 min (37.5 s/sample).