A novel method for the automatic sample preparation and analysis of 3‐MCPD‐, 2‐MCPD‐, and glycidylesters in edible oils and fats

Currently, there are three official AOCS indirect methods for the detection and quantification of 2- and 3-chloropropane-1,2-diol-(2-MCPDe/3-MCPDe) and glycidyl esters (GE). The complete analysis for methods which allow separate detection and quantification of these three analytes is time consuming (>16 h) and because of extensive manual sample preparation, the chances for error are significant and well-trained analysts are required for correct and reproducible results. We developed a new automated indirect method for sample preparation and quantification of these three analytes in oils and fats based on the relatively fast AOCS Official Method Cd 29c-13 (alkaline transesterification, differential method, no 2-MCPDe quantification). The method is adapted to ensure separate glycidol detection and correction for possible overestimation due to conversion of 3-MCPD to glycidol during alkaline transesterification using a carbon-13 labeled internal standard. Furthermore, the total analysis time is reduced significantly to less than 5 h per series of four samples with minimal contact time. The exclusion of manual sample preparation reduces the need for dedicated well-trained lab technicians and eliminates variance between technicians. This makes the automated method a suitable tool to integrate in operational Quality Control services without specialized lab technicians. The method has been validated against AOCS Official Method Cd 29b-13 using different types of edible oils. Practical application: The use of an autosampler for sample preparation simplifies the parallel analysis of MCPD and glycidyl esters to a method which can be applied in any quality control or research laboratory without the need for multiple specialized technicians while optimizing sample throughput. It minimizes analysis errors by removing the human factor during sample preparation and allows for far shorter analysis times, allowing much faster optimization of production processes and food safety quality control practices. Correction of the glycidol overestimation caused by 3-MCPD conversion to glycidol during alkaline transesterification during sample preparation using a 3-MCPD-13C3 ester as internal standard.