A simple, selective, and sensitive method for the simultaneous determination of anions (sulfate, nitrate, and chloride) and
cations (sodium, ammonium, potassium, magnesium, and calcium) in acid rain waters was developed using ion-exclusion /
cation-exchange chromatography with conductimetric detection. A weakly acidic cation-exchange resin column (Tosho
TSKgel OA-PAK-A) and a sulfosalicylic acid–methanol–water eluent was used. With a mobile phase comprising 1.25 mM
sulfosalicylic acid in methanol–water (7.5:92.5) at 1.2 ml/min, simultaneous separation and detection of the above anions
and cations was achieved in about 30 min. Linear calibration plots of peak area versus concentration were obtained over the
concentration ranges 0–1.0 mM for anions (R50.9991) and 0–0.5 mM for cations (R50.9994). Detection limits calculated
at S/N53 ranged from 4.2 to 14.8 ppb for the anions and from 2.4 to 12.1 ppb for the cations. The reproducibility of
retention times was 0.14–0.15% relative standard deviation (RSD) for anions and 0.18–0.31% for cations, and
reproducibility of chromatographic peak areas was 1.22–1.75% RSD for anions and 1.81–2.10% for cations. The method
was applied successfully to the simultaneous determination of anions and cations in aerosols transported from mainland
China to central Japan, as determined by a meteorological satellite data analyzer. Ó 2000 Elsevier Science B.V. All rights
reserved.
Keywords: Mobile phase composition; Environmental analysis; Water analysis; Ion-exclusion / cation-exchange chromatography;
Inorganic anions; Inorganic cations; Sulfosalicylic acid