Determination of Purines in Beer by HPLC Using a Simple and Rapid Sample Pretreatment

The purine contents of alcoholic beverages are usually quantified by high-performance liquid chromatography coupled with a UV detector and preceded by hydrolyzing samples with perchloric acid. In this article, we have developed an improved hydrolysis procedure in which sulfuric acid is used as the hydrolysis reagent. Through experiments under different conditions, we established the optimum sample pretreatment technique. This whole method enables four purine bases (namely, guanine, adenine, hypoxanthine, and xanthine) in beer to be determined with recoveries close to 100%, a repeatability error of less than 1%, and improved limits of detection for all the analytes was less than 5 μg/L. The overall method was successfully applied to the determination of purines in marketplace alcoholic beverages. The results showed that beers had far more total purine content (average content: 72.87 mg/L) than other alcoholic beverages (average content: 0.22 mg/L in Chinese spirits, 45.99 mg/L in rice wine, and 29.67 mg/L in wine).