A Sensitive and Specific Method for the Determination ofN-Nitrosodimethylamine in Drinking Water and Fruit Drinks

摘要

A method is described for the determination ofN-nitrosodimethylamine (NDMA) in drinking water and fruit drinks/juices. It is highly sensitive and specific, and is practically free of artifactual formation. Such formation, in this method, is minimized by distilling or extracting the samples in the presence of sulfamic acid, an excellent inhibitor ofN-nitrosation. Both gas chromatography#x2010;thermal energy analyzer (GC-TEA) and gas chromatography#x2010;high resolution mass spectrometry selected ion monitoring (GC-MS-SIM) were used for the determination of NDMA. The minimum detection limits of the two methods were 15 pg/g and 1 pg/g, respectively. The recoveries of NDMA and that ofN-nitrosodi-n-propylamine (NDPA), the internal standard, at 6.6#x2013;133 pg/g spiking levels ranged between 74#x2013;105. The efficiency of the method in preventing artifactual formation was verified by carrying out a few analyses with added marker amines such as ethylbutylamine, morpholine, and deuterium labelled dimethylamine. Several samples of contaminated water and fruit drinks contained 0.09#x2013;5.5 ng/g levels of NDMA, but those procured from retail outlets or natural sources were negative.