Determination of cholesterol and four phytosterols in foods without derivatization by gas chromatography-tandem mass spectrometry

• Main Authors: Yan-Zong Chen, Shih-Yao Kao, Hao-Cheng Jian, Yu-Man Yu, Ju-Ying Li, Wei-Hsien Wang, Chung-Wei Tsai
• Format: Article
• Language: English
• Published: Elsevier 2015-12-01
• Series: Journal of Food and Drug Analysis
• Subjects: cholesterol; gas chromatography–tandem mass spectrometry; phytosterol
• Online Access: http://www.sciencedirect.com/science/article/pii/S1021949815000393

In this study, a method for determination of cholesterol and four phytosterols by gas chromatography coupled with electron impact ionization mode–tandem mass spectrometry without derivatization in general food was developed. The sample was saponified with 7.5% KOH in methanol. After heating on hot plate and reflux for 60 minutes, the saponified portion was extracted with n-hexane/petroleum ether (50:50, v/v). The extracts were evaporated with rotary evaporator and then redissolved with tetrahydrofuran. The tetrahydrofuran layer was transferred into an injection vial and analyzed by gas chromatography on a 30 m VF-5 column. Limit of quantification was 2 mg/kg. Recoveries of cholesterol and four phytosterols from general food were between 91% and 100%.