Symposium Sessions (Day1, Day2, Day3)
Basic Sessions (Day1, Day2, Day3)
Young Researchers' Sessions (Day1, Day2, Day3)
Poster Presentations
- Day 1, May 15（Mon.） Room P (Foyer, Room 1004-1007)
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1P-21 PDF
Simultaneous Analysis of Four Carboxylic Acids in Cooking Oil by Chemical Derivatization Coupled with LC-MS/MS
Cooking oil provides several essential nutrients for human nutrition and health. Because of the heating process or improper storage condition, the oils may undergo rancid and develop an unpleasant odor/flavor owing to the formation of carboxylic acids. However, to date, the LC-MS/MS method is limited for determining carboxylic acids in cooking oil. There is also little information regarding the formation/distribution of carboxylic acids during rancidity.
We developed an LC-MS/MS method following 2,4-dinitrophenylhydrazine (DNPH) derivatization for determining four carboxylic acids, including formic acid, acetic acid, valeric acid and octanoic acid. Our results show that four carboxylic acids-DNPH derivatives have the same product ion of m/z 167 and the same feature of neutral loss of 30 Da, resulting from the DNPH fragmentation. The formation of carboxylic acids was further investigated, by incubating the carboxylic acid standard solutions with DNPH at different temperatures (37-80℃) for different periods (1-24 hr). The results show that the formation of carboxylic acids increased significantly with the increase of incubation temperature and period. Formic acid was the first to reach saturation at 80℃ for 12 hr. The present method could be useful to estimate the oil rancidity and monitor the quality of cooking oil.