Direct Analysis of Triglycerides in Edible Oils by Atmospheric Pressure Chemical Ionization Mass Spectrometry / 分析化学

ABSTRACT

An atmospheric pressure chemical ionization mass spectrometry (APCI-MS) method was developed for the direct analysis of triglycerides in edible oils.The edible oil sample was dissolved in acetonitrile.Under the optimal conditions such as positive ion detection,800 μL/h of sample flow rate,250℃ of vaporizer temperature and 5000 nA of corona needle current,the repeatability (RSD) of peak intensity rate of m/z 857.76 to m/z 881.76 was less than 5％.Then,different kinds of oil from different manufacturers were analyzed by the proposed method.After a principal component analysis for the analytical results,the peak intensity rate of m/z 857.76 and m/z 881.76 was selected for oil identification.The adulteration of 5％ lard in corn oil could be recognized directly using the peak intensity rate.Three characteristic triglycerides in edible oil were preliminarily identified by collision induced dissociation (CID) experiments.The method was applied to analyze the swill oil and fried oil samples,and the results showed that the swill oil contained both vegetable oil and animal fat,and the fried oil was also different with commercial vegetable oil.