| Condiment, such as soy sauce, oyster sauce, barbecue sauce, acid hydrolyzed vegetable protein seasoning, Seasoning powder and seasoning sauce, is an edible substance added to other foods for the purpose of giving a strong flavor or relish. As condiment is widely used in our daily lives, so its quality will seriously affect the health of consumers, and it is essential to develop a fast and precise method for determination of hazardous substances in the condiments simultaneously. The complex ingredients in condiments and interference from the matrix are the major obstacles during the process of developing methods for determination hazardous substances in the condiment.In this paper three kinds of organic pollutants whose toxicity are generally acknowledged are taken as the research object, among these chloropropanols contain 1,3-dichloro-2-propanol(1,3-DCP), 2,3-dichloro-1-propanol (2,3-DCP), 3-chloro-1, 2-propanediol(3-MCPD), methylimidazoles include 2-methylimidazole and 4-methylimidazole, while furfural, 5-methylfurfural, and 5-hydroxymethylfurfural belong to furfurals. Methods for the detection of these eight hazardous substances in different kinds of condiments by gas chromatography–tandem mass spectrometry (GC-MS/MS) were investigated and established, and the conditions of extraction, chromatography and mass spectrometry were optimized. Methodological studies, including linear range, correlation coefficient(r2), recovery, limit of determination(LOD)and precise, are conducted, and the results indicated that these methods are selective, sensitivity, accurate and rapid. The methods provide technical supports for the quality monitoring for the condiment.The specific research contents and results of our study are as follows:1.A method for the simultaneous determination of 1, 3-DCP, 2, 3-DCP, and 3-MCPD in Condimen by GC-MS/MS was established. The conditions of extraction and gas chromatography and mass spectrometry were optimized. The samples were first purified by diatomite, then the target substances were eluted with hexane/ ethyl ether (5:5, v/v), and it was derivatizated with trifluoroacetic anhydride. The three target substances were separated and detected by GC-MS/MS. Meanwhile, the fragmentation mechanisms of the target compounds were examined. In the optimized conditions, the LOD was up to 0.5μg/kg for three compounds which meets the demanding of trace analysis of 1, 3-DCP, 2, 3-DCP, and 3-MCPD in condiments.2.A method for simultaneous determination of 2-methylimidazole and 4-methylimidazole in Condimen by GC-MS/MS was developed. The samples were alkalized and purified with diatomite. The two target compounds were eluted with methylene chloride and then analyzed by GC-MS/MS in the multiple reaction monitoring mode (MRM) which can remove the interference from matrix. The linear range was 0.01～10mg/L with r2=0.9999 for 2-methylimidazole and r2=0.9997 for 4-methylimidazole. The LOD was 5μg/kg for 2-methylimidazole and 4-methylimidazole.3.A method for simultaneous determination of furfural, 5-Methylfurfural and 5-Hydroxymethylfurfural in Condimen by GC-MS/MS was proposed. The target compounds were extracted with ethyl acetate and separated by GC on a polar capillary chromatographic column, and detected by MS/MS in the MRM mode. Good linearity (r2>0.999) for three compounds were obtained in the range of 0.001～20mg/L. The LOD was 5μg/kg. The method with the simple sample procedure and without derivatization was proved to be accurate, precise and rapid... |
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