A new, direct analytical method using LC-MS/MS for fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible oils

Abstract

A new, direct analytical method for the determination of 3-chloro-1,2-propanediol fatty acid esters (3-MCPD esters) was developed. The targeted 3-MCPD esters included five types of monoester and 20 types of diester. Samples (oils and fats) were dissolved in a mixture of tert-butyl methyl ether and ethyl acetate (4:1), purified using two solid-phase extraction (SPE) cartridges (C₁₈ and silica), then analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Five monoesters and five diesters with the same fatty acid group could be separated and quantified. Pairs of 3-MCPD diesters carrying the same two different fatty acid groups, but at reversed positions (sn-1 and sn-2), could not be separated and so were expressed as a sum of both compounds. The limits of quantification (LOQs) were estimated to be between 0.02 to 0.08 mg kg⁻¹, depending on the types of 3-MCPD ester. Repeatability expressed as relative standard deviation (RSD_r%) varied from 5.5% to 25.5%. The new method was shown to be applicable to various commercial edible oils and showed levels of 3-MCPD esters varying from 0.58 to 25.35 mg kg⁻¹. The levels of mono- and diesters ranged from 0.10 to 0.69 mg kg⁻¹ and from 0.06 to 16 mg kg⁻¹, respectively.

Keywords:

• 3-MCPD esters
• LC-MS/MS
• direct determination
• edible oils

View correction statement:

A new, direct analytical method using LC-MS/MS for fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible oils

Acknowledgements

This work was performed as part of the Regulatory Research Projects for Food Safety, Animal Health, and Plant Protection of the Ministry of Agriculture, Forestry and Fisheries, Japan.