Simultaneous Determination of Hydrogen Chloride and Sulfur Dioxide in the Atmosphere By Ion Chromatography After Collection on Alkali Filters

A method for the determination of hydrogen chloride and sulfur dioxide in the atmosphere by using an alkali filter and ion chromatography was studied. The gases were collected on an alkali filter (Whatman 41 cellulose filter impregnated with 2 % Na2CO3 and 2 % glycerol). The collection efficiencies of the gases in the field measurement were>99.0 % for hydrogen chloride and 96.9 % for sulfur dioxide at a flow rate of 20 1/min. The alkali filter was extracted with the eluent solution (0.0024 M Na2CO3/0.003 M NaHCO3), and Cl-,SO32-, and SO42- were determined simultaneously by ion chromatography. The chloride represented hydrogen chloride and the combined sulfite and sulfate represented sulfur dioxide in the air sample. The oxidation of SO32- to SO42- in the solution was a problem in the spectrophotometric determination of SO32 - by using p-rosaniline, but, the problem was avoided in the ion chromatographic analysis. The proposed method. enabled the facile determination of atmospheric hydrogen chloride and sulfur dioxide at sub ppb levels. The analytical precision of the method was within 4 % for both hydrogen chloride and sulfur dioxide.