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

Yan-Zong Chen; Shih-Yao Kao; Hao-Cheng Jian; Yu-Man Yu; Ju-Ying Li; Wei-Hsien Wang; Chung-Wei Tsai

doi:10.1016/j.jfda.2015.01.010

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

J Food Drug Anal. 2015 Dec;23(4):636-644. doi: 10.1016/j.jfda.2015.01.010. Epub 2015 Apr 23.

Authors

Yan-Zong Chen¹, Shih-Yao Kao¹, Hao-Cheng Jian¹, Yu-Man Yu¹, Ju-Ying Li¹, Wei-Hsien Wang², Chung-Wei Tsai¹

Affiliations

¹ Department of Food Services, SGS Taiwan Ltd., Kaohsiung, Taiwan.
² Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung, Taiwan.

Abstract

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%.

Keywords: cholesterol; gas chromatography–tandem mass spectrometry; phytosterol.