Determination of ethanol content in industrial and domestic vinegar samples by headspace-gas chromatography

Vinegar, as a traditional fermented product, plays a significant role in human health and nutrition. This product is produced in different types industrially or domestically. Under production, the vinegar may contain ethanol that its inclusion is banned in the foods by Islam and its content should be adapted to the legislations developed in Islamic countries. Therefore, at this study we measured ethanol concentration of vinegars distributed in Tehran (capital city of Iran).

Headspace-gas chromatograph equipped with flame ionization detector was developed for determination of ethanol. Acetonitrile and nitrogen were used as internal standard and carrier gas, respectively. For analysis, 140 samples (37 domestic and 103 industrial vinegars) were purchased from local market.

Our developed method could successfully determine the ethanol content at low concentration. In this regard, LOD, LOQ, and recovery were 0.0069% v/v, 0.021% v/v, and 100.14%, respectively. In 13 samples, the ethanol content was higher than 0.5% v/v that is the maximum limit determined by Iranian national standard. Out of 13 samples, 10 vinegars were domestically prepared. Evaluation of our results revealed that ethanol concentration in domestic vinegars was higher than industrial products. Therefore, domestic production of vinegars should be controlled and monitored strictly.