Ion chromatographic determination of nitrogen dioxide and sulphur dioxide in the atmosphere using tri-ethanolamine-potassium hydroxide-coated cartridges.

Nitrogen dioxide (NO2) and sulphur dioxide (SO2) in air were sampled by the use of a Sep-Pak C18 cartridge impregnated with triethanolamine-potassium hydroxide. The trapped NO2 and SO2 were eluted with a 8 mM sodium carbonate-3 mM sodium hydrogencarbonate solution and simultaneously determined by ion chromatography. In the active sampling mode, NO2 was determined with 5.2% relative standard deviation at 95 ppb and SO2 was determined with 2.4-5.3% relative standard deviation at 54-184 ppb. The recoveries were 85-98% for NO2 and 91-105% for SO2. In the passive sampling mode, the average concentrations of NO2 and SO2 were determined with 2.4-6.8 and 2.8-7.9% relative standard deviation, respectively, at atmospheric levels for 6-24 days.