样品5.000 0 g经乙酸乙酯（20 mL+10 mL）提取，合并的提取液经C₁₈和乙二胺-N-丙基硅烷（PSA）粉末0.2 g净化，离心提取有机层，氮气吹至1 mL。所得溶液采用极性毛细管色谱柱DB-624UI进行气相色谱分离，多模式进样口（MMI）程序升温（PTV）大体积进样，多反应监测（MRM）模式下进行质谱分析。3种N-亚硝胺类化合物（N-二甲基亚硝胺、N-亚硝基吗啉、N-二丙基亚硝胺）的质量浓度在1.0~40.0 μg·L^-1范围内与其峰面积呈线性关系，测定下限（10S/N）分别为0.75，0.39，0.28 μg·kg^-1。按标准加入法在具有代表性的肉制品（火腿肠）和水产制品（烤鱼片）中分别进行回收试验，回收率在87.8%~103%之间，测定值的相对标准偏差（n=10）均小于8.0%。

The sample (5.000 0 g) was extracted with ethyl acetate (20 mL+10 mL), and the combined extract was purified with 0.2 g of C₁₈ and PSA. After centrifugation, the organic layer was concentrated to 1 mL by N₂-blowing. The obtained solution was separated by GC using the polar capillary chromatographic column DB-624 UI and program temperature vent (PTV) large-volume sample-introduction at multimode inlet (MMI). Multiple reaction monitoring (MRM) mode was adopted in MS analysis. Linear relationships between values of peak area and mass concentration of N-nitrosamine compounds (N-nitrosodimethylamine, N-nitroso morpholine and N-nitrosodipropylamine) were found in the range of 1.0-40.0 μg·L^-1, with lower limits of determination (10S/N) of 0.75,0.39,0.28 μg·kg^-1, respectively. Tests for recovery were made by standard addition method for the representative meat product (ham sausage) and aquatic product (grilled fish), giving results in the range of 87.8%-103% and RSDs (n=10) all less than 8.0%.