Abstract
A new absorbing solution containing alpha -napththol in sodium hydroxide is proposed for the collection of nitrogen dioxide. The nitrite formed is diazotized with p-nitroaniline in acidic medium which is subsequently coupled with alpha -naphthol to give purple dye in alkaline medium, which is then extracted in iso-amyl alcohol to give a deep blue color. The color reaction is proposed for the extractive spectro-photometric determination of nitrogen dioxide. The collection efficiency and NO sub(2):NO sub(2)u- stoichiometric factor are evaluated. The method is rapid, simple and free from common interferences and is successfully applied for the analysis of auto exhaust.