Determination of amino acids in selenium-enriched yeast by gas chromatography–mass spectrometry after microwave assisted hydrolysis

A simple, rapid microwave digestion procedure for protein hydrolysis preceding the determination of amino acids in yeast using gas chromatography–mass spectrometry (GC–MS) is described. Protein hydrolysis was performed in a focused microwave using 4 M methanesulfonic acid (MAS). Amino acids were derivatized with methyl chlorofomate (MCF) and extracted into chloroform prior to GC–MS analysis. The microwave parameters, including power, temperature and heating time, were optimized. It was found that temperature and heating time were the most influential factors. A total of 17 amino acids were determined in selenium-enriched yeast with use of standard addition calibration. Limits of detection and quantitation (LODs/LOQs) of the amino acids measured were in the sub-nmol range, suitable for monitoring of amino acids in yeast and other food products.

Gas chromatography mass spectrometry chromatogram of 18 amino acids extracted from selenium enriched yeast. Microwave enhanced acid hydrolysis followed by methyl chlorofomate derivatization was employed for sample preparation.Figure optionsDownload as PowerPoint slideHighlights
► A rapid microwave digestion procedure for protein hydrolysis is described.
► A simple methyl chloroformate derivatization combined with GC–MS determination was employed.
► A total of 17 amino acids were determined.
► Limits of detection in the sub-nmol range, suitable for rapid monitoring of amino acids in yeast.