冷冻除脂-气相色谱-串联质谱法检测食用植物油中30 种多环芳烃

建立冷冻除脂--气相色谱-串联质谱检测食用植物油中30?种多环芳烃（polycyclic aromatic hydrocarbons，PAH）的方法。选用6?种氘标记PAH为内标，样品经乙腈--丙酮溶液（4∶1，V/V）于离心管中涡旋提取，10?000?r/min离心5?min，－80?℃对油脂冷冻固化，倾出提取液，再经减压浓缩和氮气吹干，以二氯甲烷复溶，气相色谱--串联质谱多反应监测方式进行检测。结果表明，在相应质量浓度范围内30?种PAH均有良好线性（R2＞0.998），检出限为0.10～1.83?μg/kg，定量限为0.35～6.11?μg/kg，在5、20?μg/kg和50?μg/kg添加水平下的回收率为67.77%～119.28%，相对标准偏差为1.18%～12.47%。采用本方法对市售11?类38?个食用植物油样品的检测显示，萘、1-甲基萘、2--甲基萘、联苯、2,6--二甲基萘、苊烯、苊、2,3,6--三甲基萘、芴、二苯并噻吩、菲、蒽、1-甲基菲、荧蒽、芘、环戊烯c,d]芘、苯并a]蒽、屈、苯并b]荧蒽、苯并k]荧蒽、苯并e]芘和苯并a]芘的检出率均为100%；5--甲基屈、苝、茚并1,2,3--c,d]芘、二苯并a,h]蒽、苯并g,h,i]苝和二苯并a,l]芘的检出率分别为86.84%、63.16%、81.58%、21.05%、81.58%和26.32%；二苯并a,e]芘和二苯并a,h]芘未检出；PAH总量为92.56～905.16?μg/kg，其中苯并a]芘含量为1.94～7.40?μg/kg，依据食品安全标准限量，PAH处于较安全水平。

Determination of 30 Polycyclic Aromatic Hydrocarbons in Edible Vegetable Oils by Freeze Defatting Combined with Gas Chromatography-Tandem Mass Spectrometry

A new method was developed for the determination of 30 polycyclic aromatic hydrocarbons (PAHs) in edible vegetable oils by gas chromatography-tandem mass spectrometry (GC-MS/MS) after freeze defatting. Six deuterium labeled PAHs were used as internal standards. Samples were extracted with acetonitrile-acetone (4:1, V/V) by vortex mixing in a centrifuge tube followed by 5 min centrifugation at 10 000 r/min and freezing at ?80 ℃ for fat solidification. The extract was evaporated in a rotary vacuum evaporator and blown to dryness under nitrogen. The residue was re-dissolved in dichloromethane, and detected using GC-MS/MS in the multiple reaction monitoring mode. The calibration curves for all the analytes showed good linearity (R2 > 0.998) in their respective concentration ranges. The limits of detection (LODs) and limits of quantitation (LOQs) for 30 PAHs were in the ranges of 0.10–1.83 and 0.35–6.11 μg/kg, respectively. The recoveries varied from 67.77% to 119.28% with relative standard deviation (RSDs) of 1.18%–12.47% (n = 6) at spiked levels of 5, 20 and 50 μg/kg. The levels of 30 PAHs in 38 commercial edible vegetable oil samples from 11 different species were investigated using the GC-MS/MS method. The results showed that naphthalene, 2-methylnaphthalene, 1-methylnaphthalene, biphenyl, 2,6-bimethylnaphthalene, acenaphthylene, acenaphthene, 2,3,6-trimethylnaphthalene, fluorene, dibenzothiophene, phenanthrene, anthracene, 1-methylphenanthrene, fluoranthene, pyrene, cyclopentac,d]pyrene, benzoa]anthracene, chrysene, benzob]fluoranthene, benzok]fluoranthene, benzoe]pyrene and benzoa]pyrene were detected in all samples; the detection rates of 5-methylchrysene, perylene, indeno1,2,3-c,d]pyrene, dibenza,h]anthrancene, benzog,h,i]perylene and dibenzoa,l]pyrene were 86.84%, 63.16%, 81.58%, 21.05%, 81.58% and 26.32%, respectively; neither dibenzoa,e]pyrene nor dibenzoa,h]pyrene were detected in any of the samples. The total concentrations of 30 PAHs ranged from 92.56 to 905.16 μg/kg, and BAP varied from 1.94 to 7.40 μg/kg, which were at safe levels according to the limit standard.