氧化除杂-气相色谱/质谱联用测定食品中的石蜡

Determination of Paraffin in Food by Oxidation Purification and GC-MS

摘要:

本文建立了氧化除杂-气相色谱/质谱联用测定食品中石蜡的检测方法。样品加入环己烷超声浸提2次，离心收集浸提液，加入复配氧化试剂（三氧化铬:浓硫酸:水=1:1:2）氧化除杂，过硅胶小柱净化，气相色谱-质谱联用检测。结果表明：富含油脂的火锅底料样品方法线性范围40~800 mg/kg，相关系数0.9991，最低检测限8 mg/kg；油脂含量低的干香菇、粉条样品方法线性范围10~400 mg/kg，相关系数0.9995，最低检测限3.5 mg/kg，加标实验方法平均回收率在90~117%，相对标准偏差在2.7~6.4%。该方法反应温和，未引入干扰检测的副产物，操作简便，通用性强，适用于富含油脂的火锅底料以及油脂含量较低的干香菇、粉条、大米、瓜子等食品。

Abstract:

In this paper, an oxidation purification and GC-MS method was established for the determination of paraffin in food. Samples were extracted twice with cyclohexane and the supernatant was collected by centrifugation, then the extraction was purified by mixed oxidation reagents (chromium trioxide: concentrated sulfuric acid: water = 1: 1: 2, V/V) and silica gel column. After that, the purified extraction was detected by GC-MS. The results indicated that the linearity range, the correlation coefficient (r) and the detection limit of greasy hotpot condiment were 40~800 mg/kg, 0.9991 and 8 mg/kg, respectively; while those of the low-fat dry shiitake mushroom and vermicelli were 10~400 mg/kg, 0.9995 and 3.5 mg/kg, respectively. The recoveries ranged from 90% to 117% and the relative standard deviations were between 2.9% and 6.6%. This method is simple, sensitive and accurate, which might be used for the detection of paraffin in greasy hotpot condiment and low-fat food such as dry shiitake mushroom, vermicelli, rice and sunflower seeds.