Determination of nine nitrosamines in water by solid phase extraction and gas chromatographymass spectrometry
方法 500 mL水样通过椰壳炭填料固相萃取小柱进行NAms富集，二氯甲烷洗脱，同位素内标加入法定量，使用VF-624 MS色谱柱，气相色谱-质谱联用检测。采集上海不同类型水样以检测NAms含量。
结果 NAms待测物在10~500 ng/L范围内线性良好，相关系数均大于0.995，分别以纯水和水源水为基质，方法检出限均低于4ng/L。加标浓度为20、100、200ng/L时，纯水、水源水和管网水中NAms的加标回收率在68.7%~113%之间，相对标准偏差均在10%以下。上海不同类型水样均可检出NAms，其中N-二甲基亚硝基胺(NDMA)和N-二正丁基亚硝基胺(NDBA)检出率最高。
Background Nitrosamines in drinking water are a new group of disinfection by-products, with various kinds, high toxicity, and potential health hazards. At present, no relevant standards and methods are issued in the field of drinking water monitoring in China.
Objective This method ological study aims to develop and modify a solid phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of nine nitrosamines in drinking water and source water.
Methods Nitrosamines were extracted by passing a 500 mL water sample through a SPE cartridge composed of coconut charcoal. After elution with methylene chloride, the extracts were analyzed by GC-MS with a VF-624 MS column using isotope internal standard. Nitrosamines in different kinds of water samples collected in Shanghai were detected by the established method.
Results The calibration curves of nitrosamines had good linearity in 10-500 ng/L with correlation coefficients greater than 0.995. The method detection limits for both pure water and source water were below 4 ng/L. Recoveries ranged between 68.7%-113% with the relative standard deviations below 10% at 20, 100, and 200 ng/L for pure water, source water, and pipe water, respectively. Nitrosamines were detected in various water samples from Shanghai, with highest positive rates of N-nitrosodimethylamine (NDMA) and N-nitrosodibutylamine (NDBA).
Conclusion This method featured with high sensitivity, low detection limit, and good accuracy is applicable to the determination of nine nitrosamines in water simultaneously.