A sensitive GC-MS/MS method has been developed and validated for determining ester forms of 3-MCPD and 2-MCPD in infant formula, using 3-MCPD-d5 and 2-MCPD-d5 as internal standards, respectively. The esters of MCPDs were extracted from infant formula powder with mixture of ethanol/n-hexane/diethyl ether (1/1/1, v/v/v), then treated with sulfuric acid to release free MCPDs. Free MCPDs and internal standards were derivatized with phenylboronic acid and the corresponding derivatives were used for GC-MS/MS analysis. The chromatographic separation was performed in a DB-5MS capillary column using helium as mobile phase at flow rate of 1 mL/min. Tandem mass spectroscopic detection of each analyte was done in MRM mode by monitoring one precursor ion and two product ions. Validation results confirmed the suitability of the developed method for intended application. Application of the method in samples collected from different provinces in Vietnam detected esterified 3-MCPD in 38.9% of samples, esterified 2-MCPD in 34.7% of samples.
esters, 3-MCPD, 2-MCPD, GC-MS/MS, infant formula.
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