De Meo, M; Laget, M; Castegnaro, M; Dumenil, G
Methods for destroying some alkylating agents were investigated. Solutions containing 10.6 micromoles per milliliter (micromol/ml) dimethyl-sulfate (77781) (DMS) or 15.2micromol/ml diethyl-sulfate (64675) (DES) in acetonitrile were mixed with 1 molar (M) aqueous sodium-carbonate (497198), sodium-hydroxide (1310732), ammonia (7664417), or sodium-thiosulfate (7772987) for 8 minutes at 25 and 30 degrees-C. The extent of destruction of DMS and DES was determined by taking aliquots of the reaction mixture at 0, 1, 2, 3, 5, and 8 minutes and analyzing them for DMS and DES by high performance liquid chromatography after derivatization with p-nitrophenoxide. DMS was 100% degraded after 8 minutes' reaction with sodium-carbonate and sodium-hydroxide, 5 minutes reaction with ammonia, and 2 minutes reaction with sodium-thiosulfate. DES was 100% degraded only after 8 minutes reaction with sodium-thiosulfate. After 8 minutes reaction with sodium-carbonate, sodium-hydroxide, and ammonia the extent of DES destruction was 52.7, 65.7, and 51.2%, respectively. Additionally, 23.5micromol/ml methyl-methanesulfonate (66273) (MMS) and 36.9micromol/ml ethyl-methanesulfonate (62500) (EMS) were reacted with 1M sodium-thiosulfate. The extent of destruction of MMS and EMS was determined as before. The decomposition products of DMS, DES, MMS, and EMS were tested for mutagenicity in the Amesalmonella assay using strains (TA-97), (TA-98), (TA0100), and (TA-102) with or without metabolic activation from liver S9 mix from aroclor-1254 pretreated rats. MMS was 100% degraded after 3 minutes reaction with sodium-thiosulfate. EMS was 62.2% degraded after 8 minutes reaction. The reactions of DMS, DES, MMS, and EMS with sodium-carbonate, sodium-hydroxide, ammonia, and sodium-thiosulfate showed first order kinetics. The halflives for destruction of DMS, DES, MMS, and EMS by sodium-thiosulfate were 0.14, 1.26, 0.60, and 5.26 minutes, respectively. Except for a nonsignificant increase in mutagenic activity observed with DMS residues resulting from treatment with sodium-carbonate, sodium-hydroxide, and ammonia in strain (TA-100), none of the DMS, DES, MMS, or EMS decomposition products were mutagenic. The authors conclude that the best method for destroying DMS, DES, MMS, and EMS is to treat them with 1M sodium-thiosulfate.