Determination of p-Methoxyphenacyl Bromide Derivatives of Alkylmethylphosphonic Acids in Urine Using Gas Chromatography with High-Resolution Mass Spectrometric Detection

We developed a method for determining ethyl methylphosphonic, isopropyl methylphosphonic, isobutyl methylphosphonic, and pinacolyl methylphosphonic acids in human urine using gas chromatography with high-resolution mass spectrometry and preliminary derivatization with p -methoxyphenacyl bromide. All of the acids are specific hydrolysis products and biomarkers of nerve agents. Conditions of the derivatization reaction were optimized. Features and general patterns of the MS 1 and MS 2 spectra of derivatives acquired in electron and chemical ionization modes are revealed. The developed method achieved the limits of detection in the range from 20 to 70 ng/mL.