Identification and quantitative determination of diphenylarsenic compounds in abandoned toxic smoke canisters

Abstract

Knowledge of the exact nature of the constituents of abandoned chemical weapons (ACW) is a prerequisite for their orderly destruction. Here we report the development of analytical procedures to identify diphenylchloroarsine (DA/Clark I), diphenylcyanoarsine (DC/Clark II) and related substances employed in one of the munitions known as "Red canister". Both DA and DC are relatively unstable under conventional analytical procedures without thiol derivatization. Unfortunately however, thiol drivatization affords the same volatile organo-arsenic derivative from several different diphenylarsenic compounds, making it impossible to identify and quantify the original compounds. Further, diminishing the analytical interference caused by the celluloid powder used as a stacking material in the weapons, is also essential for accurate analysis. In this study, extraction and instrumental conditions have been evaluated and an optimal protocol was determined. The analysis of Red canister samples following this protocol showed that most of the DA and DC associated with pumice had degraded to bis(diphenylarsine)oxide (BDPAO), while those associated with celluloid were dominantly degraded to diphenylarsinic acid (DPAA).