Abstract:

A simultaneous determination method for ethyl carbamate (EC) and chloropropanols (3-monochloropropane-1,2-diol (3-MCPD) and 2-monochloropropane-1,3-diol (2-MCPD)) in flavorings was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). After spiked with internal standard, the sample was extracted by matrix solid-phase dispersion extraction technique with an Extrelut^TM NT column. Hexane was used to wash the fat soluble matrix interferences and then an ethyl acetate-ethyl ether (20:80, v/v) mixture was added to elute the analytes. The concentrated extract was detected by GC-MS/MS in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) were 2, 5 and 5 μg/kg for EC, 3-MCPD and 2-MCPD, respectively. The linear ranges were 5-1000 μg/kg (r=0.9997), 10-1000 μg/kg (r=0.9991) and 10-1000 μg/kg (r=0.9995) for EC, 3-MCPD and 2-MCPD, respectively. In soy sauce, yellow rice wine, salami sauce and flavoring of instant noodle matrices, the recoveries (RSDs, n=7) in MRM mode at the levels of 20, 100 and 400 μg/kg were 87.7%-104% (4.3%-10.7%), 90.1%-109% (2.6%-10.2%), and 90.9%-103% (3.0%-9.5%), respectively. EC, 3-MCPD and 2-MCPD were found in some real samples of the soy sauce, wine and flavoring of instant noodle. EC or 3-MCPD was found in some of the salami samples. The method is accurate, fast and suitable for the simultaneous determination of EC, 3-MCPD and 2-MCPD in flavorings.

Key words: chloropropanols, ethyl carbamate, flavorings, gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS), isotope labeled internal standard