Yan-Zong Chen ^a, Shih-Yao Kao ^a, Hao-Cheng Jian ^a, Yu-Man Yu ^a, Ju-Ying Li ^a, Wei-Hsien Wang ^b, Chung-Wei Tsai ^a,*

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

 

In this study, a method for determination of cholesterol and four phytosterols by gas chromatography coupled with electron impact ionization modeetandem 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 chromatographyetandem mass, spectrometry, phytosterol