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N-nitrosodimethylamine (NDMA) is a carcinogenic compound. The US Environmental Protection Agency (USEPA) hasestimated a 10-6 cancer risk level for NDMA in drinking water at 0.7 ng/L. Recent studiesdemonstrated that NDMA is a disinfection byproduct (DBP) associated with the use ofchloramines. However, currently there is no USEPA approved analytical method fordetermination of NDMA in drinking water. It is especially difficult at the required part-per-trillion level concentrations, due to the small molecular size and polarity nature ofNDMA. In this study, an analytical method has been developed to accurately quantify Nnitrosodimethylamine(NDMA) in drinking water using GC/MS, chemical ionizationwith methanol, and Selected Ion Storage (SIS) mode. An ion trap mass spectrometer canbe used instead of a more expensive high-resolution mass spectrometer (HRMS) todetermine NDMA at ng/L levels. Solid-phase extraction (SPE) was used with Ambersorb572 to isolate NDMA from water samples. Methylene chloride (500 uL) was used aselution solvent. Good precision was obtained, with relative standard deviation (RSD)less than 20%. The method detection limit (MDL) for SPE, using a 500 ml sample size,was 1 ng/L. The calibration of data with R2 of 0.997, data from MDL studies, resultsfrom commercial lab cross check, data from replicate reagent water samples, and realwater samples spiked with NDMA indicated that this method is acceptable fordetermination of NDMA in drinking water. The advantages of SPE processes overliquid-liquid extraction (LLE) processes were also discussed. Includes 10 references, tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 12File Size: 1 file , 290 KB