样品前处理对超高效液相色谱法分析粮食中黄曲霉毒素的影响

Effect of Sample Pretreatment on the Detection of Aflatoxin in Grain by Ultra Performance Liquid Chromatography

为优化和确立粮食中黄曲霉毒素(Aflatoxins,AFS)的前处理方法,选用自然污染的粮食样本开展研究。粮食经粉碎后提取液提取,免疫亲和柱净化,超高效液相色谱–荧光检测器定量检测。84%乙腈水的提取效率优于70%甲醇水,无需浸泡,涡旋振荡提取20 min或高速均质提取2 min,且一次提取即可提取样品中99%以上黄曲霉毒素B1。4种粮食中AFB1、AFB2、AFG1、AFG2加标回收率在86.7%~115%之间,变异系数为1.0%~12.3%之间,方法具有良好的准确性和重复性。玉米全粉、糙米粉、大米粉等粮食基质中黄曲霉毒素B1成分的国家有证标准物质的测定结果在标准值及其扩展不确定度范围内,变异系数不大于5.2%,测定结果较为满意。采用此方法参加FAPAS(PT04359)能力验证,|Z|<1,结果满意。粮食中黄曲霉毒素经84%乙腈水涡旋提取20 min或均质提取2 min提取效率高、准确性好。文献中推荐使用的70%甲醇水提取液,采用超声等提取方式可能导致测定结果偏低,无法真实反应样品中黄曲霉毒素的含量。因此,统一样品前处理方法对于原粮中黄曲霉毒素检测结果的准确性和可比性具有重要意义,本研究可为粮食中黄曲霉毒素样品前处理方法的选择提供借鉴。

To optimize and establish the pretreatment method for aflatoxins(AFS) in grains,the method was optimized by using naturally contaminated grain samples.The grains were extracted by crushing,cleaned up by immunoaffinity column,and quantified by ultra performance liquid chromatography with fluorescence detector.The results showed that the extraction efficiency of 84% acetonitrile water was better than that of 70% methanol water,without soaking,and more than 99% of aflatoxin B1 could be extracted from the samples by vortex shaking for 20 min or high-speed homogenization for 2 min.The method has good accuracy and reproducibility.The results of the determination of aflatoxin B1 components in corn flour,brown rice flour,rice flour and other grain matrices of the national certified standards were within the range of standard values and their extended uncertainties,with a coefficient of variation of 5.2%,and the determination results were more satisfactory.Using this method to participate in the FAPAS(PT04359) proficiency testing,|Z|<2,and the results were satisfactory.Aflatoxin in grain by 84% acetonitrile water vortex extraction 20 min or homogenization extraction 2 min extraction efficiency and accuracy,the literature recommended the use of 70% methanol water extraction solution,and the use of ultrasound and other extraction methods may lead to low determination results,which cannot truly reflect the content of aflatoxin in the sample.Therefore,the unification of sample pretreatment methods is important for the accuracy and comparability of aflatoxin assay results in raw grains,and this study can provide reference for the selection of sample pretreatment methods for aflatoxin in grains.