Separation of oxyanions of sulphur by single-column ion-chromatography.
After stabilization of sulphite by addition of a five-fold excess of formaldehyde, mixtures of sulphite, sulphate and thiosulphate are readily separated by HPLC. For use with Vydac columns (302IC or 300IC) a suitable eluent is 1-3mM phthalic acid (pH 5-6), and the eluted ions may be detected by means of the change in refractive index or the absorbance at 290 nm. With a flow-rate of 2 ml/min, anion elution times are about 2.7 (0.7) min for HOCH(2)SO(-)(3), 7.5 (2.6) min for SO(2-)(4) and 8.4 (5.2) min for S(2)O(2-)(3), the values in parentheses being those for the shorter 300IC column. Detection limits for sulphite and sulphate were around 1 mg/l., with relative standard deviations of 2-3% at higher levels. The sensitivity for S(2)O(2-)(3) was an order of magnitude lower. The proposed method has advantages over earlier procedures based on alkaline eluents.
Beveridge
A
A
Department of Chemistry, University of Newcastle, N.S.W. 2308, Australia.
Pickering
W F
WF
Slavek
J
J