Direct Derivatization and Rapid GC-MS Screening of Nerve Agent Markers in Aqueous Samples

Abstract

A rapid screening and identification method based on derivatization and gas chromatography mass spectrometry (GC-MS) has been developed for the detection of alkylphosphonic acids (APAs), the degradation products of organophosphorus nerve agents. The novel method described involves rapid (5 min) and direct derivatization of 25 microL aqueous sample using highly fluorinated phenyldiazomethane reagents (e.g., 1-(diazomethyl)-3,5-bis(trifluoromethyl)benzene). The APA derivatives are then screened by GC-MS negative ion chemical ionization (NICI) and identified by electron ionization (EI) mode. The conditions for the derivatization were optimized using statistical experimental design and multivariate data analysis. Method robustness was evaluated using aqueous samples from an official OPCW Proficiency Test and all APAs present in the sample were conclusively identified. Limits of detection for rapid screening using SIM NICI were between 5 and 10 ng/mL APA in aqueous sample, and for identification using full scan EI 100 ng/mL.

Three-phase hollow fiber liquid-phase microextraction of organophosphorous nerve agent degradation products from complex samples

“…However, phosphonic acids being not volatile enough, a step of derivatization has to be performed before GC analysis [2][3][4]. This step of derivatization is still time-consuming and can suffer from matrix effects in real samples [5].…”

An isomer-specific high-energy collision-induced dissociation MS/MS database for forensic applications: a proof-of-concept on chemical warfare agent markers

“…In brief, the acids were derivatized rapidly and directly in aqueous samples by using the reagent 1‐(diazomethyl)‐3,5‐ bis ‐(trifluoromethyl)benzene at room temperature for 5 min in an ultrasonic bath. Deuterium reference compounds pinacolyl d 3 ‐methylphosphonic acid and n ‐hexyl d 3 ‐methylphosphonic acid were synthesized and derivatized similarly . The silylation of the reference chemicals was achieved with 10% BSTFA in acetonitrile at 60°C for 30 min.…”

“…An external proficiency test sample (PT19, aqueous sample W1), provided by the Organisation for the Prohibition of Chemical Weapons, was derivatized as described earlier . The sample contained three isomers of hexyl methylphosphonic acid, namely, pinacolyl methylphosphonic acid (isomer R9), 1‐methylpentyl methylphosphonic acid (isomer R5) and 4‐methylpentyl methylphosphonic acid (isomer R2), each at a concentration of 6 µg/mL.…”

“…The hexyl methylphosphonic acid isomers in aqueous samples were derivatized as described previously by this laboratory. [25] In brief, the acids were derivatized rapidly and directly in aqueous samples by using the reagent 1-(diazomethyl)-3,5-bis-(trifluoromethyl)benzene at room temperature for 5min in an ultrasonic bath. Deuterium reference compounds pinacolyl d 3 -methylphosphonic acid and n-hexyl d 3 -methylphosphonic acid were synthesized and derivatized similarly.…”

An ultrasensitive method of real time pH monitoring with complementary metal oxide semiconductor image sensor

“…Certainly, conventional analytical tools such as high-performance liquid chromatography (HPLC) [27], gas chromatography (GC) [28], capillary electrophoresis and mass spectroscopy are considered as the most reliable system for the chemical analysis [29]. However, expensive device, requirements of well trained operator, time-consuming process and non-portability are reasons for the peoples associate with modern sensors.…”