Submitted for oral presentation MCPD and Glycidyl Esters in Food Products – Occurrence, Methods and Analytical Facts G. Karanikolopoulos , D. Chrysafidis, V. Tzamtzis and D. Tsipi A Chemical Division, General Chemical State Laboratory (GCSL), Athens, Greece e-mail: g.karanikolopoulos@2009.syzefxis.gov.gr To improve consumer acceptance, edible vegetable oils are industrially processed by removing or modifying components that can negatively impact appearance, taste, odour and self-life of the final consumer product. Nonetheless, undesirable chemical side reactions can take place during the refining process which result in the presence of potentially hazardous chemical compounds in thus produced fats and oils. Fatty acid esters of 3- Monochloropropane-1,2-diol (3-MCPDEs), 2-Monochloropropane-1,3-diol (2-MCPDEs) and 2,3-Epoxy-1-propanol (GEs), are contaminants generated in the above processes. The non- esterified 3-Monochloropropane-1,2-diol (3-MCPD) was classified as a possible human carcinogen with a tolerable daily intake (TDI) of 2 μg/kg b.w. (currently modified to 0.8. μg/kg b.w). Accordingly, EU legislation has been enacted, specifying maximum levels for 3- MCPD in hydrolysed vegetable proteins (HVP) and soya sauce [1]. Moreover, it has been demonstrated that the toxicity of 3-MCPDEs should be considered equivalent (on a molar basis) to that of the parent compound. GEs have been assessed to be carcinogenic/genotoxic. For the 2-MCPDEs no toxicological effects could be concluded due to lack of data, but they are still under scrutiny [2]. In recent years, these categories of contaminants have been identified in various food items [3]. Setting maximum permitted levels in food for 3-MCPDEs and GEs seems to be of high priority for the European Commission. On analytical stand point the determination of MCPDEs and GEs presents several hurdles, concerning both the isolation of the analytes from different food matrices (extraction procedure) as well as the analytical process itself (i.e. challenging separation, risk of isomerisation or transformation of the analytes). In this aspect concerns have been raised regarding the reliability of results obtained from currently available analytical methods applied in various food matrices. In the present work an optimised indirect analytical protocol for the simultaneous determination of 3-MCPDEs, 2-MCPDEs and GEs by an isotope dilution gas chromatography mass-spectrometry (GC-MS) technique has been developed and tested in different food samples. The current protocol includes liquid-liquid extraction of the fat phase from the initial food matrix, formation of 3-Monobromopropane-1,2-diol (3-MBPD) esters from GEs, and finally acid transesterification and derivatisation of the released free form in ethyl acetate with phenylboronic acid (PBA). The PBA derivatives are consecutively measured by GC-MS with electron ionisation (EI) in SIM mode. The adopted method was in compliance with internationally accepted criteria (in terms of trueness and precision) and was validated for the scopes of the study. Furthermore, the applied analytical protocol was utilised for the analysis of food samples derived from the local market and results are presented and discussed. References [1] EU Commission Regulations N° 466/2001and N° 1881/2006 [2] EU Recommandations 2014/661; EFSA CONTAM Panel, Scientific Opinion, EFSA Journal, 2016, 14(5):4426 [3] Z. Zelinková et al., Food Addit. Contam., 23(2006), 1290–1298; V. G. Samaras et al., J. Chromatogr. A, 1466(2016), 136–147