Determination of 6 Inorganic Anions in Beer by Ion Chromatography

Beer sample (10.0 mL) was degassed ultrasonically for 30 min, and then purified on activated SPE column. 2.0 mL of the purified solution was diluted with water to 20.0 mL, filtered on 0.22 μm filtering membrane and the filtrate was used for IC analysis. The anion exchange column IonPac AS11 was used for separation with column temperature at 35 ℃ and KOH solutions of various concentrations produced by a KOH eluant generator were used in gradient elution, with flow-rate of 1.0 mL·min^-1. Linearity ranges for 6 inorganic anions (Cl^-, NO₂^-, Br^-, NO₃^-, SO₄^2- and PO₄^3-) were kept between definite mass concentrations. Values of detection limits (3S/N) were in the range of 0.005-0.028 mg·L^-1. With a same beer sample, test for precision was made, giving values of RSDs (n=6) in the range of 2.1%-3.0%. Test for recovery was made by standard addition method, giving results in the range of 89.0%-105%.