SIMULTANEOUS ANALYTICAL METHOD FOR 1,4- DIOXANE ANDN-NITROSOAMINES USING SOLID PHASE EXTRACTION ANDGC/MS/MS/CI FROM AQUEOUS SAMPLES

摘要

Among the emerging contaminants in the surface and treated wastewater,nitrosamines and 1,4-Dioxane are very prevalent contaminants in the watersystems. The formation mechanism of N-nitrosdimethyl amine (NDMA) in thewater treatment facility has been an urgent task to reduce NDMA in the finaleffluent. The mass consumption of 1,4-dioxane in many industrial applications formany years influenced level of this compound not only in surface water but alsoin groundwater with the significant concentrations between 2 part per billion and3,000 part per billion.Orange County Water District (OCWD) Laboratory has developed cost-effectiveand very sensitive detection method for NDMA and 1,4-dioxane usingGC/MS/MS/CI and GC/MS/MS/Purge-Trap, respectively. Since the demand ofthese methods is very high to process over 2,000 samples each year. The labinitiated the multi-residual analytical method to incorporate 1,4-dioxane with theexisting analytical method for nitrosamines. The solid phase extraction (SPE)with 80 to 100 meshes of granular carbon uses 10 ml of methylene chloride forextracting the interested analytes from the absorbent materials. The 10 ml extractwas concentrated to final volume of 1ml to be analyzed by GC/MS/MS withpositive chemical ionization with methanol reagent solution.The developed analytical method generated the acceptable recovery and precisionfor both nitrosamines and 1,4-dioxane for different matrix of aqueous samplessuch as ground water, surface water and reclaimed water. The reportabledetection limit of 1,4-dioxane was 0.05part per billion while the purge-trapmethod was 1.0 part per billion.