Ion chromatographic determination of common ions at ultratrace levels in Antarctic snow and ice

The simultaneous determination of major impurities present in Antarctic snow and ice at ng g^? (ppb) concentrations by ion chromatography is described. Calibration data are presented for ammonium, sodium, potassium, chloride, nitrate and sulphate ions. Special attention is paid to the different ways of removing field contamination from ice and snow cores and suitable equipment is described. The results provide evidence against the validity of published sets of concentration data for nitrogen-containing compounds (NO^?₃ and NH⁺₄ in Antarctic snow, and demonstrate a crucial contamination problem in the determination of ammonium ions.