ANALYSIS OF SNOW FROM ANTARCTICA - A CRITICAL APPROACH TO ION-CHROMATOGRAPHIC METHODS

Ion-chromatographic methods for anion and cation determination in snow samples from Antarctica are evaluated with regard to sensitivity and selectivity. An eluent-step change method is proposed to determine simultaneously mono- and divalent cations with detection limits lower than 1 mug/L. Special attention is given to the determination of the ammonium ion at trace levels in the presence of high sodium concentrations and the problems of sample contamination by the laboratory environment are evaluated. Two alternative methods, one using isocratic and the other a gradient elution, are proposed for the determination of fluoride, acetate, formate and methanesulphonate ions. Both methods are discussed to evaluate their use in snow sample analysis.