IC Determination of Inorganic Anions and Cations in Soil

The contents of 6 anions and 4 cations in soil were determined by ion chromatography (IC). IonPac AS11-HC column with 30 mmol·L-1 KOH solution as eluant was used for separation of the 6 anions, i.e., F-, Cl-, NO2-, NO3-, SO42- and PO43-, and IonPac CS12A column with 20 mmol·L-1 methyl sulfonic acid as eluant was used for separation of the 4 cations, i.e., Na+、K+、Mg2+ and Ca2+. Inhibitory conductivity detections were adopted in the determination. Linearity was found in the definite ranges for all the 10 ions, with values of detection limits (3S/N) of 5.0 μg·L-1 for F-, 5.0 μg·L-1 for Cl-, 6.1 μg·L-1 for NO2-, 6.8 μg·L-1 for NO3-, 5.8 μg·L-1 for SO42- and 10.0 μg·L-1 for PO43-, 6.2 μg·L-1 for Na+, 5.1 μg·L-1 for K+, 10.0 μg·L-1 for Mg2+ and 10.0 μg·L-1 for Ca2+. The proposed method was applied to the determination of 10 inorganic ions in soil, giving values of recovery in the range of 95.6%-103%.