2-Monochloro-1,3-propanediol (2-MCPD) Dynamics in DGF Standard Methods and Quantification of 2-MCPD

Abstract

Pure 2-monochloro-1,3-propanediol (2-MCPD) was successfully synthesized, identified, and first quantified by the Deutsche Gesellschaft für Fettwissenschaft (DGF) standard method C-VI 18 (10), with a calculable detection sensitivity relative to 3-monochloro-1,2-propanediol (3-MCPD) of 3.26-fold, using a QP-2010 GC/MS instrument. The detection sensitivities of other GC/MS instruments can be determined using the individual ion-ratio of the fragment to the precursor of 3-MCPD-d ₅ as a reference. Quantification of 2-MCPD is possible using conventional 3-MCPD-d ₅ esters as internal-standards, without a calibration curve of pure 2-MCPD. The dynamics of 2-MCPD during DGF standard methods C-VI 18 (10) were directly analyzed using NMR and indirectly using GC/MS. 2-MCPD was partly converted to glycidol under basic conditions of the transesterification step, and the glycidol was reconverted to 2-MCPD under acidic conditions of the extraction step. 2-MCPD spiked in soybean oil was detected as 98 mol% 2-MCPD and 2 mol% 3-MCPD from the area ratio in GC/MS. In contrast, glycidyl stearate spiked in soybean oil was detected as 5.5–5.7 mol% 2-MCPD and 94.3–94.5 mol% 3-MCPD from the corrected area ratio in GC/MS.