In-situ derivatization and headspace solid-phase microextraction for gas chromatography-mass spectrometry analysis of alkyl methylphosphonic acids following solid-phase extraction using thin film.

A headspace solid-phase microextraction (HS-SPME) method, involving solid-phase extraction and in-situ derivatization using polymeric thin film, was developed for the gas chromatography-mass spectrometry (GC-MS) analysis of the degradation products of nerve agents. The solid-phase extraction (SPE) was performed using poly([2-(Methacryloyloxy)ethyl]trimethylammonium chloride) film on a gold plate prepared via surface-initiated polymerization. The extracted analytes were directly derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) on the plate. Various parameters like fiber type, headspace time, temperature, and amount of BSTFA were optimized. Under the optimized conditions, the relative standard deviations (RSDs) were in the range 7.0-13.1% and the limits of detection (LODs) were measured to be between 10 and 20 pg mL. The application of the developed method was tested using the 35th Organization for Prohibition of Chemical Weapons (OPCW) proficiency test sample.