Analysis of chemical warfare agents in organic liquid samples with magnetic dispersive solid phase extraction and gas chromatography mass spectrometry for verification of the chemical weapons convention.
A simple, sensitive and low temperature sample preparation method is developed for detection and identification of Chemical Warfare Agents (CWAs) and scheduled esters in organic liquid using magnetic dispersive solid phase extraction (MDSPE) followed by gas chromatography mass spectrometry analysis. The method utilizes Iron oxide@Poly(methacrylic acid co ethylene glycol dimethacrylate) resin (Fe2O3@Poly(MAA co EGDMA) as sorbent. Variants of these sorbents were prepared by precipitation polymerization of methacrylic acid co ethylene glycol dimethacrylate (MAA co EGDMA) onto Fe2O3 nanoparticles. Fe2O3@poly(MAA co EGDMA) with 20% MAA showed highest recovery of analytes. Extractions were performed with magnetic microspheres by MDSPE. Parameters affecting the extraction efficiency were studied and optimized. Under the optimized conditions, method showed linearity in the range of 0.1 3.0mgmL( 1) (r(2)=0.9966 0.9987) The repeatability and reproducibility (relative standard deviations (RSDs) were in the range of 4.5 7.6% and 3.4 6.2% respectively for organophosphorous esters in dodecane. Limits of detection (S/N=3/1) and limit of quantification (S/N=10/1) were found to be in the range of 0.05 0.1mgmL( 1) and 0.1 0.12mgmL( 1) respectively in SIM mode for selected analytes. The method was successfully validated and applied to the extraction and identification of targeted analytes from three different organic liquids i.e. n hexane, dodecane and silicon oil. Recoveries ranged from 58.7 to 97.3% and 53.8 to 95.5% at 3mgmL( 1) and 1mgmL( 1) spiking concentrations. Detection of diethyl methylphosphonate (DEMP) and O Ethyl S 2 diisopropylaminoethyl methylphosphonothiolate (VX) in samples provided by the Organization for Prohibition of Chemical Weapons Proficiency Test (OPCW PT) proved the utility of the developed method for the off site analysis of CWC relevant chemicals.
Journal of chromatography. A