Spectrophotometric determination of sulphur dioxide and hydrogen sulphide in gas phase by sequential injection analysis technique

Methods for determination of H2S and SO2 in gas phase have been developed. The methods are based on absorption of the gases in scrubbing solutions and subsequent sequential injection analysis (SIA) determination of the absorbed gases. The reagents used in the SIA measurements, pararosaniline for SO2 and nitroprusside for H2S, are very specific for the analytes. Absorbance of the reaction products is measured at 558nm. The methods have been developed for determination of SO2 in the range 1.6-8.0g/m^3 and H2S in the range 5-15g/m^3. The relative standard deviation of the determinations is less than 2.5% (n=10). The methods developed are intended for on-line monitoring of H2S and SO2 in gas generated when heating coal at coke production.