Analytical methods based on liquid chromatography for the analysis of albumin adducts involved in retrospective biomonitoring of exposure to mustard agents.

The objective of the present review is to list, describe, compare, and critically analyze the main procedures developed in the last 20 years for the analysis of digested alkylated peptides, resulting from the adduction of albumin by different mustard agents, and that can be used as biomarkers of exposure to these chemical agents. While many biomarkers of sulfur mustard, its analogues, and nitrogen mustards can easily be collected in urine such as their hydrolysis products, albumin adducts require blood or plasma collection to be analyzed. Nonetheless, albumin adducts offer a wider period of detectability in human exposed patients than urine found biomarkers with detection up to 25 days after exposure to the chemical agent. The detection of these digested alkylated peptides of adducted albumin constitutes unambiguous proof of exposure. However, their determination, especially when they are present at very low concentration levels, can be very difficult due to the complexity of the biological matrices. Therefore, numerous sample preparation procedures to extract albumin and to recover alkylated peptides after a digestion step using enzymes have been proposed prior to the analysis of the targeted peptides by liquid chromatography coupled to mass spectrometry method with or without derivatization step. This review describes and compares the numerous procedures including a number of different steps for the extraction and purification of adducted albumin and its digested peptides described in the literature to achieve detection limits for biological samples exposed to sulfur mustard, its analogues, and nitrogen mustards in the ng/mL range.

Three-phase hollow fiber liquid-phase microextraction of organophosphorous nerve agent degradation products from complex samples.

Degradation products of chemical warfare agents are considered as important environmental and biological markers of chemical attacks. Alkyl methylphosphonic acids (AMPAs), resulting from the fast hydrolysis of nerve agents, such as sarin and soman, and the methylphosphonic acid (MPA), final degradation product of AMPAs, were determined from complex matrices by using an emergent and miniaturized extraction technique, the hollow fiber liquid-phase microextraction (HF-LPME), before their analysis by liquid chromatography coupled to mass spectrometry (LC-MS). After studying different conditions of separation in the reversed phase LC-MS analysis, the sample treatment method was set up. The three-phase HF-LPME was carried out by using a porous polypropylene (PP) hollow fiber impregnated with 1-octanol that separates the donor and acceptor aqueous media. Various extraction parameters were evaluated such as the volume of the sample, the effect of the pH and the salt addition to the sample, the pH of the acceptor phase, the extraction temperature, the stirring speed of the sample, the immersion time in the organic solvent and the time of extraction. The optimum conditions were applied to the determination of MPA and five AMPAs in real samples, such as surface waters and urine. Compounds were extracted from a 3 mL acidified sample into only 6 µL of alkaline water without any other pretreatment of the complex matrices. Enrichment factors (EFs) higher than 170 were obtained for three less polar AMPAs. Limits of quantification (LOQs) in the 0.013-5.3 ng mL(-1) range were obtained after microextraction of AMPAs from river water and in the range of 0.056-4.8 ng mL(-1) from urine samples with RSD values between 1 and 9%.