Analysis of Processing Contaminants in Edible Oils. Part 2. Liquid Chromatography–Tandem Mass Spectrometry Method for the Direct Detection of 3-Monochloropropanediol and 2-Monochloropropanediol Diesters

Abstract

A method was developed and validated for the detection of fatty acid diesters of 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) in edible oils. These analytes are potentially carcinogenic chemical contaminants formed during edible oil processing. After separation from oil matrices using a two-step solid-phase extraction (SPE) procedure, the target compounds are quantitated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). The first chromatographic conditions have been developed that separate intact diesters of 2-MCPD and 3-MCPD, allowing for their individual quantitation. The method has been validated for 28 3-MCPD diesters of lauric, myristic, palmitic, linolenic, linoleic, oleic, and stearic acids in coconut, olive, and palm oils, as well as 3 2-MCPD diesters, using an external calibration curve. The range of average recoveries and relative standard deviations (RSDs) across the three oil matrices at three spiking concentrations are 88-118% (2-16% RSD) with maximum limits of quantitation of 30 ng/g (ppb).

Direct determination of fatty acid esters of 3-chloro-1, 2-propanediol in edible vegetable oils by isotope dilution - ultra high performance liquid chromatography - triple quadrupole mass spectrometry

“…to previously reported methods [31,[33][34][35]39,40,44,46], lower LODs were obtained in the present method (Table 4). For the extraction and cleanup of 3-MCPD esters in edible oil samples, the matrix interferences of MSPD cleanup in this study should be lower than that of the "Direct dilution and injection" method [36,47].…”

“…A mixture of 0.05% of formic acid and 2 mmol L −1 ammonium formate in 2-propanol/water (98: 2) (phase A) and methanol/water (92: 8) (phase B) was ultimately selected as the mobile phase, to obtain a sufficiently good performance for ionization of 3-MCPD esters along with a good peak symmetry. And the identical mobile phases were used in previous investigation [40].…”

“…However, the fatty acids from the unsymmetrical 3-MCPD diesters in the sn-1 and sn-2 position were not lost equally, which produced product ion profiles had relative intensities of between 2.5 and 4 (sn-2/sn-1 fatty acid). According to MacMahon [40], the two monitored transitions for a given analyte produced different results, and the MS/MS fragment produced by the loss of NH 4 Cl was appropriate for the quantitation of unsymmetrical 3-MCPD diesters in processed oil samples, because it produced the identical response for the two unsymmetrical 3-MCPD diesters and is not impacted by sn-1/sn-2 isomerism. But the transition was much lower sensitivity of that transition compared to the loss of a fatty acid.…”

“…Analysis of monoester and diester fractions can clearly provide detailed information on the individual esters, which is important for the toxicological studies or the understanding of the pollution profile of different 3-MCPD esters. However, the direct methods for 3-MCPD esters have not taken into the separation of 3-MCPD esters and 2-MCPD esters with the exception of the study by MacMahon [39][40][41], which has separated three pairs of monoester isomers and eleven pairs of diester isomers.…”

Chloropropanols, Chloropropandiols and Their Esters in Food – Formation, Occurrence, Determination, Reduction of Content

“…Autorzy opracowali metodę (z walidacją) bezpośredniego oznaczania diestrów 3-MCPD. Przedstawili także wyniki oznaczeń diestrów nasyconych kwasów tłuszczowych (C12 -C18) oraz kwasów C18:1, C18:2 i C18:3 z 3-MCPD w różnych matrycach [48]. Podsumowaniem tej serii jest publikacja [47], w której autorzy przytaczają wyniki bezpośrednich oznaczeń sumarycznej zawartości estrów 3-MCPD, z podziałem na zawartość estrów poszczególnych kwasów tłuszczowych w 116 próbkach różnych olejów jadalnych oraz szorteningów pochodzą-cych z handlu detalicznego USA.…”