Determination of passive-sampled sulphur dioxide in ambient air as sulphate ion by flow injection analysis with an in-line reaction column

摘要

A modified FIA methqd was developed for the determination of sulphur dioxide (SO_2) in ambient air collected by a passive sampler. SO_2 was oxidized by hydrogen peroxide and determined as sulphate ion in solution. Barium-dimethylsulfoazo-III complex was used as spectrophotometric reagent. A BaSO_4-immobilized in-line reaction column was introduced into the flow system to increase the sensitivity and reproducibility. An in-line cation exchange column was used to eliminate triethanolamine. which was used as the absorbent reagent in the passive sampler. Sulphate ions can be analyzed in the range of 0.08-10.00 mg 1~(-1) with the R.S.D. less than 1.6% at the rate of 15 samples h~(-1). It was satisfactory to apply this method to the analysis of sulphur dioxide in ambient air and the results agreed with those obtained by ion chromatography.