Sulfur dioxide (SO2) monitors are based on amperometry, in which an electrical current is measured that is proportional to the SO2 in a collecting solution. Sulfur dioxide can be determined using ion chromatography by bubbling SO2 through hydrogen peroxide solution to produce SO4, followed by analysis of the sulfate by ion chromatography, a method that separates ions on a chromatography column and detects them very sensitively by conductivity measurement.