Abstract: A new ion chromatographic (IC) method was developed for the determination of alkali metal (Li+, Na+, and K+), alkali-earth metal (Mg2+ and Ca2+) cations and ammonium (NH4+) in four types of alcoholic beverages including yellow rice, Chinese liquor and red wine and beer. The separation of cations was performed on IonPac CG16 (5 mm × 50 mm) and IonPac CS16 (5 mm × 250 mm) columns connected in series with 30 mmol/L methanesulfonic acid as an eluent. The calibration plots obtained for conductivity detection of the separated cations showed a good linearity with regression coefficients (r2) > 0.999 0 and the method presented good reproducibility with low values of relative standard deviation (RSD) ≤ 5.52 (n = 6). The results of IC analysis indicated the presence of ammonium in 18 brands of yellow rice wines at concentrations ranged from 137.00 to 284.01 mg/L and in beer and red wine at concentrations ranged from 28.29 to 42.88 mg/L, but the absence of ammonium in Chinese liquor. A further investigation revealed that the elevated concentration of ammonium in yellow rice wine was due to the presence of proteins in the raw materials, indicating the ammonium concentration depends on the fermentation degree. At the same time, no correlation between ammonium content and age was found for yellow rice wine. The concentrations of alkali metal and alkaline-earth metal cations were the lowest in Chinese liquor as compared with the other types of beverages studied, which could be due to distillation during its production. It was also found that the concentration of K+ in red wine was significantly higher than in the other types, which was attributed to the higher content of potassium in red grapes.

Key words: cation, yellow rice wine, alkali metal cations, magnesium, calcium, ammonium, fermentation, brewing