Proposals for the improving of the existing GC-FID methods for determination of methanol and volatile compounds in alcoholic beverages

In this work, proposals for improving the official gas chromatography flame ionization detector (GC-FID) methods for the determination of volatile congeners in alcoholic beverages are presented. The method based on the use of ethanol as an internal standard for the determination of 10 principal volatile compounds was developed, validated and compared with the official method in terms of analytical quality parameters (repeatability, intermediate precision, limits of detection and quantification, linearity and accuracy). The relative difference between results, obtained during test of 25 real samples of alcoholic beverages (rum, whiskey, bourbon, brandy, calvados, grappa, slivovice, tsikoudia, vodka, gin, grain spirit, liqueurs (herbal, limon, cherry, raspberry, sloe gin, egg and sambuca), vermouth, sake, nalewka, glühwein and rectified spirit), for the developed and official methods varies in the range from − 1.3 to 0.9% and statistically insignificant at 0.05 significance level (Student’s test and ANOVA). The usage of the developed modified internal standard method allows to reduce minimal volume of sample from 200 to 1 mL and eliminate sources of uncertainty, associated with the sample preparation (distillation, density determination, and addition of an internal standard compound). The results of the conducted study show that the developed method can improve the official method, but additional interlaboratory study are required. Graphical abstract