Analytical method for the trace determination of esterified 3- and 2-monochloropropanediol and glycidyl fatty acid esters in various food matrices

摘要

In 2014, the European Food Safety Authority (EFSA) requested the Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC) to develop a reliable analytical method for the determination of fatty acid esters of 3-monochloropropanediol (3-MCPDEs), of 2-monochloropropanediol (2-MCPDEs) and of glycidol (GEs) in a broad variety of food samples, and to test its applicability in routine on about 500 different food samples. The provision of an analytical method was urgently required within the scope of monitoring the occurrence of these substances in food, which is necessary for the exposure estimations. The lack of occurrence data was accompanied by concerns regarding the applicability and reliability of results obtained with the available methods for processed food. This article presents an indirect analytical procedure for the simultaneous determination of 3-MCPDEs, 2-MCPDEs and GEs in a wide variety of food products after extraction by pressurised liquid extraction (PLE) and gas chromatography mass-spectrometry (GC-MS) detection. For the differentiation of MCPDEs and GEs, GEs were first converted to monobromopropanediol esters (MBPDEs) in aqueous acid bromide solution. MCPDEs and MBPDEs were then hydrolysed under acidic conditions followed by derivatisation of the released free (non-esterified) form in ethyl acetate with phenyl boronic acid (PBA). Quantification of the analytes was carried out using the isotopic labelled analogues of both MCPDEs and GEs. Limits of detection (LODs) and limits of quantitation (LOQs) were, expressed on fat basis, in the range of 7 - 17 mg kg−1 and 13 - 31 mg kg−1 respectively, while the working range of the method was between LOQ and 1.850 mg kg-1 (expressed on fat basis). The performance characteristics of the proposed analytical method were compliant with the criteria specified by EFSA and the European Commission. The developed method was successfully applied for the analysis of the target compounds in more than 650 different food samples covering the following categories: bread and rolls, fine bakery wares, smoked fish products, fried and roasted meat, potato based snacks and fried potato products, cereal-based snacks and margarines.