Major Inorganic Ions in Polish Beers

Abstract

Reliable determination of various components of beers is still a challenge due to their complex matrices. Inorganic ions are very important components of beer; their content depends mainly on the quality of water and additional substances used in the brewing process. The major inorganic anions (F-, Cl-, NO2-, NO3-, PO43-, SO42-) and cations (Na+, K+, Mg2+ and Ca2+) were determined using isocratic ion chromatography with conductivity detection. Method optimization involved six ion-exchange columns; different eluent concentration and flow rates were tested. Optimized methodologies allowed for quick, selective and reliable analysis of these ions in 30 beers available on the Polish market. They were characterized by pH values from 3.19 to 4.64, and conductivity from 1632 to 2662 µS/cm. The content of inorganic anions ranged from 0.2 - 1.1 mg/L for F-; 8 - 235 mg/L for Cl-; NO2- < LOD; 7 - 22 mg/L for NO3-; 44 - 188 mg/L for PO43-, and 10 - 95 mg/L for SO42-. In case of cations, it was 10 - 93 mg/L for Na+; 87 - 329 mg/L for K+; 54 - 329 mg/L for Mg2+, and 10-89 mg/L Ca2+. PCA Principal Component Analysis helped in establishing similarities between the analyzed samples.