Gas chromatographic determination of acetic acidin wine using ethyl acetate extraction

Abstract

'Geographical Indication (GI) Hokkaido' has been operating since 2018 with the aim of ensuring the quality and branding of wine produced in Hokkaido. The amount of volatile acid, mostly acetic acid, should be regulated for GI certification since excessive amounts contribute to objectionable off-flavors of wine. In this study, a new application of gas chromatography (GC) followedby ethyl acetate extraction was examinedas a simple andreliable methodof measuring acetic acidin wine. Higher reproducibility (RSD: 2.1% to 4.4%) was observedin three types of wine samples with different acetic acidconcentrations (254 to 756 μg/mL), accompaniedby satisfactory recoveries (98% to 102 %). The determination range was 254 to 1 236 μg/mL, well covering the required criterion (<1 000 μg/mL). Significant correlations were recognizedbetween the GC methodandhigh-performance liquidchromatography (HPLC), which has been approvedas a screening methodfor measuring volatile acidin GI wine (r=0.993, p<0.0001, n=22), and also the distilled-titration method (r=0.974, p<0.0001, n=19). Thus, the proposedGC methodfor the determination of acetic acidin wine samples is simple andreliable; furthermore, it will be useful as an alternative reference based on a different principle to the traditional titration method or the prevalent HPLC method.