改进的QuEChERS-气相色谱-质谱法测定中式腊肉中8 种挥发性N-亚硝胺

基于改进的QuEChERS法建立测定中式腊肉中8 种挥发性N-亚硝胺的气相色谱-质谱检测方法，并应用于市售样品的初步风险评估。样品经乙腈超声提取、冷冻和N-丙基乙二胺净化后水浴氮吹浓缩定容至微量体积；目标物经极性毛细管柱分离后以选择离子监测模式和外标法定量。结果表明，8 种N-亚硝胺在对应质量浓度范围内线性关系良好（R2＞0.997），基质效应为0.86～0.98；检出限为0.05～0.14 μg/kg，定量限为0.15～0.47 μg/kg；低、中、高3 个含量（0.3、1.0、3.0 μg/kg）加标回收实验的平均回收率为71.3%～94.1%，相对标准偏差（n=6）为0.4%～11.2%；12 份代表性市售样品中仅1 份样品的N-亚硝基二乙胺含量（3.06 μg/kg）超标，其余均低于单项和总挥发性N-亚硝胺的限量水平（3.0 μg/kg和10.0 μg/kg）。该方法净化效果好、成本低，检测灵敏、结果准确，适用于中式腊肉中8 种挥发性N-亚硝胺的检测；目前市售中式腊肉中N-亚硝胺的风险水平整体较低。

Determination of Eight Volatile N-Nitrosamines in Chinese Bacon by Modified QuEChERS and Gas Chromatography-Mass Spectrometry

A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) protocol coupled to gas chromatography-mass spectrometry (GC-MS) method for the determination of eight volatile N-nitrosamines in Chinese bacon was established and applied to evaluate the risk of dietary exposure to N-nitrosamines in commercial samples. The samples were extracted with acetonitrile in an ultrasonic bath, and after freezing treatment, the extract was purified using primary secondary amine (PSA) and condensed by nitrogen blowing in water bath to a trace volume. Then, the N-nitrosamines were separated on a polar capillary column, detected in the selected ion monitoring (SIM) mode and quantified by the external standard method. The results showed that the calibration curves exhibited good linearity for the eight volatile N-nitrosamines (R2 > 0.997) with matrix effects between 0.86 and 0.98. The limits of detection (LODs) and the limits of quantification (LOQs) ranged from 0.05 to 0.14 μg/kg and from 0.15 to 0.47 μg/kg, respectively. The average recoveries at three spiked levels (0.3, 1.0 and 3.0 μg/kg) were between 71.3% and 94.1% with relative standard deviations (n = 6) in the range of 0.4%–11.2%. Only one of the 12 representative samples sold on the market showed a N-nitrosodiethylamine (NDEA) content exceeding the national standard limit (3.06 μg/kg), while the rest were lower than the limits for individual and total volatile N-nitrosamine (3.0 and 10.0 μg/kg, respectively). This method showed the advantages of good purification effect, low cost, high sensitivity and good accuracy, and was suitable for the detection of the eight volatile N-nitrosamines in Chinese bacon. And the risk level of dietary exposure to N-nitrosamines in Chinese bacon was relatively low overall.