Determination of organic acid anions in Italian beers by a new HPLC method

摘要

A simple method was developed to determine organic acids in beer using very common laboratory equipment and easy sample preparation. Four Italian brands of lager type beer were used. Beer samples were applied to an anion exchange resin and organic acids were released using 0.1 N HCl. HPLC separation was achieved using two C-18 reverse phase columns in series. Acids were separated and quantified by isocratic analysis (0.8 mL/min in 30 min). Pyruvic, malic, lactic, acetic, citric, succinic, citramalic and fumaric anions in beer were detected using Refractive Index (RI) and Ultraviolet (UV) detectors. Use of the resin bed gave a good efficiency of recovery evaluated with the two detectors. Responses of the two detectors were also statistically comparable when the organic acid anion composition of the four different brands was evaluated. The RI detector was 10 times less sensitive than the UV detector, but still quite sufficient to detect the lowest concentration of organic acid anions in beer.