A method validation of modified pressurized liquid extraction - gas chromatography-mass spectrometry for the determination of 3- and 2- monochloropropanediols fatty acid esters and glycidol esters in selected food products / Noor Asma Shaari

The aim of the study is to establish the detection method for 3-, 2- monochloropropanediols Fatty Acid Esters (MCPDE) and glycidol Esters (GE) using modified pressurized liquid extraction (PLE) and gas chromatography mass-spectrometry (GC-MS). The PLE was adopted and modified (duration time of heating and number of static cycles) for reduced solvent volume and process time (to extract lipid from chocolate spread, infant formula, potato chips and sweetened creamer. The solvent selected for PLE was a mixture of iso-hexane and acetone at 100 °C with the lipid and analyte recovery ranging from 96.9% to 98.6% and 84.1% to 107.5%, respectively. The derivatization of analytes was adopted from American Oil Chemists’ Society Official (AOCS) method Cd29a-13 for GC-MS analysis. The results showed that the coefficient of determination (R2) of all analytes was > 0.99. The limit of detection (LOD) was 0.1 mg kg-1 expressed in lipid basis for both 3- and 2-MCPDE, and 0.2 mg kg-1 expressed in lipid basis for GE. The limit of quantitation (LOQ) was 0.3 mg kg-1 expressed in lipid basis for both 3- and 2-MCPDE, and 0.6 mg kg-1 expressed in lipid basis for GE. A blank spiked with 3- and 2-MCPDE (0.3, 2.1 and 7.2 mg kg-1) and GE (0.6, 4.7 and 16.6 mg kg-1) were chosen for accuracy and precision tests. The recoveries were between the range of 91.7% to 105.9%. Both repeatability and within-laboratory reproducibility of the analysis were within the acceptable level of precision ranging from 1.7% to 16%. This is the first time that full validation procedure extending to both accuracy and precision tests was carried out for sweetened creamer and chocolate spread. Overall, the combined protocol of modified PLE and AOCS Cd29a-13 was successfully validated for both solid and liquid food samples with lipid content from 10% to 30%. A validated method was applied to determine the concentration of 3-, 2- MCPDE and GE in chocolate spread, evaporated creamer, sweetened creamer, milk product and potato chips using modified Pressurised Liquid Extraction -Gas Chromatography-Mass Spectrometry. A total of 56 samples was selected from the retail market in Malaysian. The levels of 3-, 2- MCPDE and GE ranged from 0.1 mg kg-1 to 4.84 mg kg-1. Chocolate spread was found to contain the highest concentration of 3- and 2- MCPDE at 4.84 mg kg-1 and 3.37 mg kg-1, respectively. Meanwhile, potato chips contained the highest amount of GE at 4.07 mg kg-1. The principal component analysis (PCA) showed that the 3-, 2- MCPD and glycidol contents was negatively correlated with fatty acid C16:0 (palmitic acid) and C18:0 (stearic acid).