Alternative Internal Standard Calibration of an Indirect Enzymatic Analytical Method for 2-MCPD Fatty Acid Esters

An indirect enzymatic analysis method for the quantification of fatty acid esters of 2-/3-monochloro-1,2-propanediol (2/3-MCPD) and glycidol was developed, using the deuterated internal standard of each free-form component. A statistical method for calibration and quantification of 2-MCPD-d₅, which is difficult to obtain, is substituted by 3-MCPD-d₅ used for calculation of 3-MCPD. Using data from a previous collaborative study, the current method for the determination of 2-MCPD content using 2-MCPD-d₅ was compared to three alternative new methods using 3-MCPD-d₅. The regression analysis showed that the alternative methods were unbiased compared to the current method. The relative standard deviation (RSD_R) among the testing laboratories was ≤ 15% and the Horwitz ratio was ≤ 1.0, a satisfactory value.