全二维气相色谱-飞行时间质谱测定婴幼儿配方奶粉中的矿物油

Determination of mineral oil in infant formula by comprehensive two-dimensional gas chromatography with time of flight mass spectrometry

中文关键词:  全二维气相色谱-飞行时间质谱法  饱和烃类矿物油  芳香烃类矿物油  婴幼儿配方奶粉

英文关键词:comprehensive two-dimensional gas chromatography with time of flight mass spectrometry  mineral oil saturated hydrocarbons  mineral oil aromatic hydrocarbon  infant formula

中文摘要:

      目的 建立全二维气相色谱-飞行时间质谱(two-dimensional gas chromatography with time of flight mass spectrometry, GC×GC-TOFMS)/氢火焰离子化检测器(flame ionization detector, FID)法测定婴幼儿配方奶粉中矿物油的分析方法。方法 样品经过提取皂化、0.3%(质量分数)硝酸银硅胶-分子筛硅藻土混合固相萃取(solid phase extraction, SPE)?柱净化处理后, 采用全二维气相色谱-飞行时间质谱联用进行检测和分析。结果 该法实现了饱和烃类矿物油(mineral oil saturated hydrocarbons, MOSH)和芳香烃类矿物油(mineral oil aromatic hydrocarbons, MOAH)的在线分离, 仪器分析时间仅为34 min。MOSH和MOAH的检出限为0.5 mg/kg, 加标回收率为88.0%~97.2%, 相对标准偏差为5.0%~8.3% (n=6)。运用该法对20款配方奶粉进行测定, 均未检出MOAH, 其中11款检出MOSH,含量为0.5~8.2 mg/kg; 奶粉中普遍含有奇数碳的正构烷烃和植物甾醇烯类物质, 推断矿物油污染可能来源于油墨和润滑油。结论 方法灵敏, 进一步提高了定量的准确性, 可同时进行定性和定量分析,适合于奶粉中矿物油的检测。样品检测结果表明, 婴幼儿配方奶粉中矿物油的污染情况需引起关注。

英文摘要:

      Objective To establish a method for the determination of mineral oil in infant formula by comprehensive two-dimensional gas chromatography with time of flight mass spectrometry (GC×GC-TOFMS) with flame ionization detector (FID). Methods The sample was extracted and saponified, and purified by solid-phase extraction (SPE) cartridge mixed by 0.3% silver nitrate silica gel and molecular sieve diatomite, then followed by quantitative and qualitative analysis by GC×GC-TOFMS. Results The method could effectively separate the mineral oil saturated hydrocarbon (MOSH) and mineral oil aromatic hydrocarbon (MOAH) online, and the time for instrument analysis was only 34 min. The detection limit of MOSH and MOAH was 0.5 mg/kg, and the spiked recoveries was 88.0%–97.2% with the standard deviations was 5.0%~8.3% (n=6). Total of 20 kinds of samples were measured using the established method, and MOAH was not detected in infant formula, but MOSH was detected in 11 samples, with the content of 0.5–8.2 mg/kg. Infant formula generally contained odd-numbered n-alkanes and plant steradienes and the contamination of mineral oil was suspected to be from ink and lubricant. Conclusions This method is sensitive and the accuracy of quantification is further improved. It can be used for simultaneously qualitative and quantitative determination of mineral oil in milk powder. The result of sample test shows that the contamination of mineral oil in infant formula should be paid more attention.