SEPARATION OF CHEMICAL WARFARE AGENT DEGRADATION PRODUCTS BY THE REVERSAL OF ELECTROOSMOTIC FLOW IN CAPILLARY ELECTROPHORESIS

We report the development of analyses for nerve agent degradation prod ucts or related species by the reversal of electroosmotic now in capil lary electrophoresis (CE), The developed methods were used in this lab oratory for analysis of samples in the second and third official profi ciency tests (International Round-Robins) for the Provisional Technica l Secretariat/Preparatory Commission for the Organization for the Proh ibition of Chemical Weapons, and those results are reported here, Anal ytes studied include methylphosphonic acid (a dibasic acid), the monoi sopropyl ester of ethylphosphonic acid, and the monoalkyl esters of me thylphosphonic acid (R = ethyl, isopropyl, isobutyl, pinacolyl (3,3-di methyl-2-butyl), cyclohexyl, and 2-ethylhexyl). The cationic surfactan ts used here for the reversal of electroosmotic now are didodecyldimet hylammonium hydroxide and cetyltrimethylammonium hydroxide, CE methods using conductivity or indirect UV detection provide a good separation efficiency and very high sensitivity for the analysis of such compoun ds, The detection limits for these species were about 75 mu g/L when u sing conductivity detection and about 100 mu g/L when using indirect U V detection, Because pH plays an important role in the CE separation o f the alkylphosphonic acids and their monoesters, the influence of pH on these separation systems was investigated, Electrolytes were stable for at least 3 months, Excellent separation efficiency and freedom fr om interference due to common anions were obtained in the developed me thods which typically achieved complete separations in less than 3 min , The method was applied to aqueous leachates of soil, wipes of surfac es, and vegetation sampled from a held site known to have been exposed to nerve agents and subsequently cleaned up, The data from these envi ronmental samples indicated that the method can be expected to be usef ul for environmental monitoring.