Quantitation of five organophosphorus nerve agent metabolites in serum using hydrophilic interaction liquid chromatography and tandem mass spectrometry

Abstract

Although nerve agent use is prohibited, concerns remain for human exposure to nerve agents during decommissioning, research, and warfare. Exposure can be detected through the analysis of the hydrolysis products in urine as well as blood. An analytical method to detect exposure to five nerve agents, including VX, VR (Russian VX), GB (sarin), GD (soman) and GF (cyclosarin), through the analysis of the hydrolysis products, which are the primary metabolites, in serum has been developed and characterized. This method uses solid phase extraction coupled with high performance liquid chromatography for separation and isotopic dilution tandem mass spectrometry for detection. An uncommon buffer of ammonium fluoride was used to enhance ionization and improve sensitivity when coupled with hydrophilic interaction liquid chromatography resulting in detection limits from 0.3–0.5 ng/mL. The assessment of two quality control samples demonstrated high accuracy (101–105%) and high precision (5–8%) for the detection of these five nerve agent hydrolysis products in serum.

Modification of human serum albumin by the nerve agent VX: microbore liquid chromatography/electrospray ionization high‐resolution time‐of‐flight tandem mass spectrometry method for detection of phosphonylated tyrosine and novel cysteine containing disulfide adducts

“…Concluding, verification of exposure to CWA plays an important role in the way that unambiguous confirmation of an alleged use of banned substances by military or terrorist forces may have far‐reaching political and legal impact. However, direct detection of CWA in vivo is quite difficult due to rapid clearance from the circulation and structural changes in the course of biotransformation processes . Therefore, current efforts are focused on identification of adducts between CWA and endogenous target molecules (e.g.…”

“…However, direct detection of CWA in vivo is quite difficult due to rapid clearance from the circulation and structural changes in the course of biotransformation processes. [2,[4][5][6] Therefore, current efforts are focused on identification of adducts between CWA and endogenous target molecules (e.g. proteins), as these biomarkers are still detectable days or even weeks after exposure.…”

Bridging the gap between sample collection and laboratory analysis: using dried blood spots to identify human exposure to chemical agents

“…OPNA metabolites were extracted from the dried sample using methanol coupled with a small volume of aqueous internal standard; this combination achieved ~100% recovery of all analytes from the DBS with a short incubation period at room temperature. The direct extraction of OPNA metabolites from DBS resulted in minimal matrix effects (−2.27–2.24%), eliminating the need for additional sample preparation such as solid phase extraction as was necessary for the wet whole blood, plasma, and serum samples 11, 17 . Precision ranged from 6.17–14.2% and accuracy ranged from 93.6–111% for two quality control samples at 30 and 250 ng/mL assessed over a period of 66 days, with a maximum of two analyses per day.…”

A high‐throughput UHPLC–MS/MS method for the quantification of five aged butyrylcholinesterase biomarkers from human exposure to organophosphorus nerve agents

“…(Black, 2010) Nerve agent metabolites can be detected in blood and urine; however, these metabolites are excreted from the body within two weeks following exposure. (Hamelin et al, 2014, Mawhinney et al, 2007, Riches et al, 2005) OPNAs also form protein adducts which can provide a previously reported two to three months for retrospective detection. (Black and Read, 2013) The Ellman activity assay has been used to determine OPNA exposure by measuring cholinesterase activity but lacks the specificity to distinguish OPNAs from organophosphorus pesticides or other compounds capable of inhibiting cholinesterases.…”