| Summary: | 碩士 === 國立中央大學 === 化學研究所 === 99 === Abstract
Disinfection has successfully applied to eliminate pathogens in various water supplies, however its byproducts (DBPs) cause unintended health risks to human. N-nitrosodimethylamine (NDMA) is one of the most toxic DBPs that raises the cancer risk. Due to its high toxicity, nowadays, the presence of NDMA and other N-nitrosamines in water is an emerging issue since many of them are suspected to be human carcinogens. They are also listed in the Unregulated Contaminant Monitoring Rule 2 (UCMR-2) by US-EPA.
In this study, a simple sample pretreatment technique, dispersive micro-solid phase extraction (dMSPE), was developed for the extraction of NDMA and other N-nitrosamines (NAs) from aqueous samples. The parameters affecting the extraction efficiency were systematically investigated and the conditions optimized. The best extraction conditions involved the immersed 75 mg of carbon molecular sieve, carboxen 1003 (as adsorbent), in a 50 mL water sample containing 5% of sodium chloride in a sample tube. After 20 min of shaking extraction, the adsorbent was collected under rapidly filtered, and 150 ?L of dichloromethane was used to elute NAs from the adsorbent. The extract 10 ?L was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry (GC-CI/MS) under selected ion storage mode. The limits of quantitation (LOQs) were less than 0.9 ng/L. The method was validated through a recovery study of various environmental
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samples. Concentrations of NDMA in swimming pool water samples were detected ranging 4.7 to 127.4 ng/L, and recovery ranged from 57-113% and the relative standard deviation was below 20%. This developed method is a simple and solvent-less pretreatment method to detect NDMA and other N-nitrosamines in aqueous sample.
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