Chromatography–mass spectrometry determination of alkyl methylphosphonic acids in urine

Abstract

The potentials of different chromatography–mass spectrometry methods for the determination of alkyl methylphosphonic acids (AMPAs)—the chemical markers of nerve agents in urine—are compared. The gas chromatography–mass spectrometry (GC–MS) characteristics of various volatile AMPA derivatives are studied. The preference of perfluorobenzyl derivatives over methyl, trimethylsilyl and tert-butyldimethylsilyl esters for the GC–MS determination of AMPAs in urine is demonstrated. An optimal technique for the determination of AMPAs in urine is HPLC combined with high-resolution MS² mass spectrometry with the isotope–labeled forms of target compounds as internal standards. The detection limits of AMPAs in the proposed analytical procedures vary from 0.1 to 1.0 ng/mL.