Evaluation of the matrix effect in the gas chromatographic determination of methanol in alcohol products

Abstract

The effect of matrix components on the results of gas chromatographic determination of methanol in samples of alcoholic and alcohol-containing products was studied using a modified internal standard method for quantitative calculations. Ethanol, which is the main component of alcoholic products was used as an internal standard. The matrix effect can be attributed to the presence of ethanol in various contents, and volatile and non-volatile impurity components characteristic of different kinds of drinks. The matrix effect was evaluated by the spike test in the study of 24 samples of alcoholic and alcohol-containing products with a volume fraction of ethanol from 6.5 to 96.6%. All samples were subjected to distillation: the initial samples and distillates were analyzed at a low sugar content; whereas at a high sugar content, only distillates were analyzed. It is shown that the effect of matrix components on the results of the determination of methanol by the proposed method is statistically insignificant. The developed method is characterized by lower financial, material, labor and time costs compared to the current technical regulatory legal acts of the EAEU, China, India, the EU, USA and Mexico. Validation of the method can be performed on the basis of data regularly obtained by the laboratory during routine study of alcoholic products, without using any additional reagents, equipment and additional measurements. Moreover, the method has good prospects for standardization at the interstate and international levels, i.e., in the framework of the activities of the Euro-Asian Council for Standardization, Metrology and Certification (EASC) and the authoritative International Organization of Vine and Wine (OIV).