IC Determination of 6 Organic and Inorganic Anions in Soil with Conductivity Detector and UV-Detector in Series

Six organic and inorganic anions including n-butyrate, oxalate, bromide, iodide, chloride and sulfate in soil were determined by ion chromatography (IC) with conductivity detector and UV-detector connected in series. The sample (10.00 g) was extracted ultarsonically with 50 mmol·L-1 NaOH solution (50 mL) for 60 min. After centrifugation, the supernatant was filtered with 0.22 μm membrane and purified on OnGuardⅡP column. The eluate after diluting 5 times with water was separated on IonPAC AG18 column using KOH solutions of different concentrations as mobile phase in gradient elution. The 5 anions besides I- were detected with conductivity detector and iodide ion was detected by UV-detector at 236 nm. Linear relationships between values of peak area and mass concentration of the 6 anions were kept in definite ranges with values of detection limits (3S/N) in the range of 0.013-0.095 μg·g-1. Values of recovery given by standard addition method were in the range of 92.0%-112%, with values of RSD′s (n=6) ranged from 1.2% to 7.2%.