Determination of volatile compounds in cider spirits by gas chromatography with direct injection

Abstract

Two analytical methods based on gas chromatography with direct injection are described for the quantitative analysis of volatile compounds (acetals, aldehydes, esters, alcohols, and volatile phenols) in cider brandies. Analytes were divided into major, 15, and minor volatile, 24, compounds depending on their usual concentration in samples. Parameters usually tested for method validation are evaluated. Correlation coefficients are calculated to estimate linearity, obtaining values higher than 0.999. Detection limits range between 0.325 mg/L (1-propanol) and 1.663 mg/L (methanol) among the major volatile compounds and between 0.086 mg/L (ethyl 2-methylbutyrate) and 0.332 mg/L (ethyl tetradecanoate) among the minor volatiles. Mean recoveries ranged between 109% (ethyl lactate) and 95% (1-butanol) for major volatiles and between 109% (1-octen-3-ol) and 94% (ethyl 2-methylbutyrate) for minor volatiles, thus confirming the accuracy of both methods. Reproducibility for major volatiles is < 5.4% (furfural) in all cases and < 9.6% (hexyl acetate) for minor volatiles. Moreover, the accuracy of the methods is evaluated by analyzing a certified whisky and five samples from interlaboratory assays, generally obtaining results in accordance with previous values.