Method "Ethanol as Internal Standard" for determination of volatile compounds in alcohol products by gas chromatography in daily practice

TL;DR

The paper investigates a new gas chromatography method using ethanol as an internal standard for measuring volatile compounds in alcohol products, demonstrating its accuracy, consistency, and suitability for standardization.

Contribution

It introduces and validates a novel method that simplifies and standardizes the determination of volatile compounds in alcohols using ethanol as an internal standard.

Findings

Relative bias does not exceed 10% for all compounds.

Response factors are constant over time and across GC models.

Method is suitable for implementation in international standards.

Abstract

Recently proposed new method "Ethanol as Internal Standard" for determination of volatile compounds in alcohol products by gas chromatography (GC) is investigated from different sides including method testing on prepared standard solutions like cognac and brandy, different ethanol-water solutions and certified reference material CRM LGC5100 Whisky-Congeners. Analysis of obtained results of experimental study from four different laboratories shows that relative bias between the experimentally measured concentrations calculated in accordance with proposed method and the values of concentrations assigned during the preparation by gravimetric method for all analyzed compounds does not exceed 10 %. It is shown that relative response factors (RRF) between analyzed volatile compounds and ethanol do not depend on time of analysis and are constant for every model of GC. It is shown the possibility to use predetermined RRF in daily practice of testing laboratories and to implement this new method in the international standards of measurement procedure.