A coulometric iodimetric procedure for measuring the purity of lewisite

A new analytical method for the determination of the purity of CASARM Lewis ite samples (Chemical Agent Standard Analytical Reference Materials) has be en developed and tested. The method essentially replaces the volumetric iod imetric procedures currently in use with the in-situ electrochemical genera tion of iodine. Tests on both arsenious acid and Lewisite/CVAA solutions sh ow that the method is capable of achieving high accuracy and precision. Sam ple preparation and analysis times are considerably less than the current t itrimetric method. The coulometric iodimetric method has been shown capable of determining not only total organic trivalent arsenic, but also total tr ivalent arsenic merely by adjusting the pH. Organic arsenic is determined a t pH 4, and total trivalent arsenic at pH 8. (C) 2001 Elsevier Science B.V. All rights reserved.