固相萃取-大体积程序升温进样气相色谱-三重四极杆串联质谱测定饮用水中3种挥发性N-亚硝胺

建立了固相萃取大体积程序升温进样气相色谱-三重四极杆质谱联用(GC-QqQ-MS/MS)同时测定饮用水中N-亚硝基二甲胺、N-亚硝基甲基乙基胺及N-亚硝基二乙基胺的分析方法。用椰壳活性炭固相萃取小柱萃取水样中待测物组分,少量二氯甲烷洗脱、无水硫酸钠脱水,大体积程序升温进样,气相色谱-三重四极杆质谱联用仪进行多反应监测(MRM)模式检测,外标法定量。3种N-亚硝胺在1～50 ng/L范围内线性关系良好,相关系数(r^2)均大于0.999,在饮用水中进行10、20和50 ng/L水平的添加,3种待测物平均加标回收率为94.8%～109%,相对标准偏差(RSD)为4.44%～8.10%(n=5),定量限(LOQ)为0.08～0.7 ng/L。该法灵敏、准确、简单、可靠,适用于饮用水中3种N-亚硝胺组分的痕量检测。

Determination of three volatile N-nitrosamine in drinking water by solid phase extraction and gas chromatography-triple quadrupole mass spectrometry with programmable temperature vaporizer-based large volume injection

A method had been developed for the determination of three N-nitrosamines, namely, N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), and N-nitrosodiethylamine (NDEA) in drinking water by solid phase extraction (SPE) and gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS) with programmable temperature vaporizer (PTV)-based large volume injection (LVI). The N-nitrosamine compounds were extracted from the water sample using a solid phase extraction (SPE) cartridge filled with coconut charcoal, and then eluted with 10 mL methylene chloride. The eluate was dried by anhydrous sodium sulfate and 10 μL was injected into the GC-MS/MS by PTV-LVI. The target compounds were detected by the multi-reaction monitoring (MRM) mode, and quantified with the external standard method. The results showed that the three compounds had good linearities in the range of 1-50 ng/L with correlation coefficients (r²) higher than 0.999. Drinking water samples were spiked with the target compounds at three concentration levels (10, 20, and 50 ng/L), and satisfactory recoveries (between 94.8% and 109%) and good reproductivities (relative standard deviation RSD<10%) were achieved. The limits of quantitation (LOQs) of the three N-nitrosamines were found to be in the range of 0.08-0.7 ng/L. The developed method was sensitive, accurate, convenient, and reliable for the determination of the three trace level N-nitrosamines in drinking water.