Analytical Methodology And Application Of Trace N-nitrosamines In Groundwater

N-Nitrosamines(NAs)are trace organic contaminants of environmental concern with high carcinogenicity.It has been discovered in recent years that the NAs widely presented in different water sources.Therefore,the monitoring of distribution,concentration and source of NAs in groundwater has attracted much attention.In this study,9 kinds of typical N-nitrosamines,including N-nitroso-dimethylnitrosamine(NDMA),N-nitroso-methyl-ethylamine(NMEA),N-nitrosodiethylamine(NDEA),N-nitrosodi-N-propylamine(NDPA),N-nitrosodibutylamine(NPIP),N-nitrosopiperidine(NDBA),N-nitrosopyrrolidine(NPYR),N-nitrosomorpholine(NMOR)and N-nitrosodiphenylamine(NDPhA),often detected in groundwater samples were selected as targets.Solid phase microextraction(SPME)pretreatment enrichment technology combined with gas chromatography tandem quadruples mass spectrometry(GC-MS/MS)has been employed to develop analytical methodology,and applied into groundwater samples analysis.The main contents of this study are described as follows:(1)The GC-MS-MS instrumental analysis method for the determination of nine N-nitrosamines was established with a WAX(0.25m 0.25mm 30m)capillary column.Under the optimized conditions,9kinds of N-nitrosamines showed good separation efficiency,peak shape and there is no sharp trailing phenomenon.It has been found that the Multi Reaction Monitoring(MRM)method showed a lower detection limit and high stability than those of Single Ion Monitoring(SIM).(2)Solid phase microextraction(SPME)pretreatment methods were established for N-nitrosamines analysis in groundwater samples.Under the optimal conditions,the nine N-nitrosamines showed a good linearity in the concentration range of 0.1~5.0?g/L(R~2?0.9960),with the detection limit of 32~63 ng/L.The recovery results ranged from68.50%~117.06%with the relative standard deviation(RSD)of1.44%~14.40%.Compared with the solid phase extraction(SPE)method,the SPME method was faster,cheaper and more accurate and could serve as an ideal method for N-nitrosamines analysis in water.(3)Practical application of the N-nitrosamines analysis in 31groundwater samples collected from Changzhou and Wuxi regions.It was found that N-nitrosamines have been detected in 23 samples with 74.2%detection probability,although a slight variation in concentration and types of N-nitrosamines were also found between two regions.In general,the screening results of N-nitrosamines in these samples indicated that the protection of underground water quality is very necessary in China.