Fast Ion Chromatographic Method for the Determination of Formates in Alcoholic Drinks

Monitoring of human exposure to formic acid is important due to its high biological activity. Elevated amounts of formic acid in the human body can cause serious damage to optical nerve, respiratory failure, renal failure, deep metabolic acidosis, coma, and eventual death from cardiovascular arrest. Such symptoms are characteristic for methanol poisoning owing to rapid enzymatic conversion of methanol into formic acid of substantially higher than methanol alone toxicity. Early diagnosis of methanol consumed and formic acid produced is essential for successful medical treatment. Small amounts of methanol can be introduced into the human body with alcoholic drinks (methanol can be a by-product of distillation and fermentation processes). A fast method for the determination of formates in commercial alcoholic drinks by the use of suppressed ion chromatography (IC) with conductometric detection has been developed. The applicability of two anion-exchange columns, Metrohm Metrosep A Supp 7 and Dionex IonPac AS9-HC, for selective detection of formates in mixtures with acetates and common inorganic ions occurring in such kind of samples was examined. Quantitative isolation of formates from the matrix can be reached in less than 10 min using 3.6 mmol/L Na2CO3 as an eluent. Preliminary minimizing of alcoholic matrix by the evaporation (under IR source) allows to improve the quality of chromatographic results. The evaluated amounts of formates in two different Polish commercial products, "Absolwent vodka" and "Golden Rum," tested in the work were in the range of 0.2-3.1 mg/L. The 96-107% recoveries of the formates from the examined samples were found out.