Extraction approaches for A-230, A-234, VX, and sarin nerve agents from surface coatings

Nerve agents are among the most hazardous chemical warfare agents (CWAs) due to their extreme toxicity. This study optimized methods for extracting CWAs (A-230, A-234, VX, and sarin) from surface coatings, a common but chemically complex matrix in urban environments. Four types of coatings (nitrocellulose, polyurethane, acrylic, and alkyd) were tested using bulk, wipe, and scrape extraction approaches with various solvents. Versatile methods were successfully developed for all four analytes across all four matrices, and recoveries were also determined for additional CWAs (soman, cyclosarin, and sulfur mustard). Bulk extraction consistently achieved the highest recoveries, while wipe extraction offered a practical alternative with slightly reduced efficiency. Scrape extraction exhibited high variability and was unsuitable for volatile compounds like sarin. The methods were evaluated using gas chromatography with flame ionization detection, demonstrating robust analytical performance, including high sensitivity, precision, minimized matrix effects, and validated accuracy through spiking recoveries. Persistence studies revealed slow dissipation rates in surface coatings, underscoring their forensic potential when other matrices yield only degradation products. A-230 and A-234 were detectable in all coatings for up to 56 days, whereas sarin dissipated rapidly, especially in acrylic paint. VX remained primarily in surface layers due to its high viscosity and limited diffusion. These findings highlight the importance of tailoring extraction methods to specific matrices and agents. Coatings, with their prolonged retention of CWAs, not only provide significant forensic value but also emphasize the need for targeted decontamination strategies to mitigate environmental and human health risks.