Analysis of Volatile Acids in Food by Headspace Gas Chromatography-Mass Spectrometry

A headspace gas chromatography-mass spectrometry(HS/GC-MS)method was developed and validated for determination of volatile acids including acetic acid,propionic acid,butyric acid,iso-valeric acid,valeric acid,3-methylpentanoic acid,caproic acid,heptanoic acid,caprylic acid,nonanoic acid and capric acid,in food.The volatile acids were isolated from samples using a headspace(HS)system,then identified and quantified by GC-MS.The experimental conditions were optimized and the performance of the system was evaluated.Under the optimal conditions,Linear calibration curves were obtained with correlation coefficients of more than 0.998 6.The linear range is between 0.20-5 mg/L.The detection limits were in the range of 0.000 2-35.5 mg/L,which was lower one to three levels than that of the scan method.The average recoveries of 11 volatile acids ranged from 93% to 99% with RSDs less than 10%.The method was simple,rapid,reproducible and accurate,and was suitable for the quantitative analysis of volatile acids in food.