Zelinkova Zuzana, Giri Anupam, Wenzl Thomas
European Commission, Joint Research Centre, Retieseweg 111, B-2440 Geel, Belgium.
Food Control. 2017 Jul;77:65-75. doi: 10.1016/j.foodcont.2017.01.024.
Fatty acid esters of 2- and 3-chloropropanediol (MCPDEs) and fatty acid esters of glycidol (GEs) are commonly monitored in edible fats and oils. A recommendation issued by the European Commission emphasizes the need of generating data on the occurrence of these substances in a broad range of different foods. So far, analytical methods for the determination of MCPDEs and GEs are fully validated only for oils, fats and margarine. This manuscript presents the assessment of critical steps in the AOCS Cd 29a-13 method for the simultaneous determination of MCPDEs and GEs in the fat phase obtained from bakery and potato products, smoked and fried fish and meat, and other cereal products. The trueness of the method is affected by the additional formation of 3-MBPD esters from monoacylglycerols (MAGs), which are frequently present in food. The overestimation of GE contents for some samples was confirmed by the comparison of results with results obtained by an independent analytical method (direct analysis of GE by HPLC-MS/MS). An additional sample pre-treatment by SPE was introduced to remove MAGs from fat prior to the GEs conversion, while the overall method sensitivity was not significantly affected. Trueness of the determination of GEs by the modified analytical procedure was confirmed by comparison with a direct analysis of GEs. The potential impact on accuracy of results of the final sample preparation step of the analytical procedure, the derivatization of free forms MCPD and MBPD with PBA, was evaluated as well. Different commercial batches of PBA showed differences in solubility in a non-polar organic solvent. The PBA derivatization in organic solvent did not affect precision and trueness of the method due to the isotopic standard dilution. However, method sensitivity might be significantly compromised.
2-氯丙二醇和3-氯丙二醇的脂肪酸酯（MCPDEs）以及缩水甘油的脂肪酸酯（GEs）通常在食用油脂中受到监测。欧盟委员会发布的一项建议强调，需要收集这些物质在各类不同食品中存在情况的数据。到目前为止，仅针对油脂、人造黄油，MCPDEs和GEs的分析方法才得到充分验证。本手稿介绍了对AOCS Cd 29a - 13方法中关键步骤的评估，该方法用于同时测定从烘焙食品、土豆制品、烟熏和油炸鱼及肉类以及其他谷物制品中获得的脂肪相中MCPDEs和GEs的含量。该方法的准确性受到单酰甘油（MAGs）额外生成3 - MBPD酯的影响，而MAGs在食品中经常存在。通过将结果与独立分析方法（通过HPLC - MS/MS直接分析GE）获得的结果进行比较，证实了某些样品中GE含量的高估。在GEs转化之前，引入了SPE额外样品预处理以从脂肪中去除MAGs，而整体方法灵敏度未受到显著影响。通过与GE的直接分析比较，证实了改进分析程序测定GEs的准确性。还评估了分析程序最终样品制备步骤（游离形式的MCPD和MBPD与PBA衍生化）对结果准确性的潜在影响。不同商业批次的PBA在非极性有机溶剂中的溶解度存在差异。由于同位素标准稀释，在有机溶剂中进行PBA衍生化不会影响该方法的精密度和准确性。然而，方法灵敏度可能会受到显著影响。
