Abstract
An extraction method for determining nitrite in water was 30% more sensitive than the standard spectrophotometric method. The nitrate is used to diazotize o-nitroaniline. The o-nitrophenyldiazonium chloride formed is coupled with N-(1-naphthyl)ethylenediamine dihydrochloride in acid medium to give a red-violet dye (absorption maxima at 545 nm) which is stable and extractable into isoamyl alcohol. The color system obeyed Beer 's law in the range 2.5-15 micro g of nitrite per 25 ml of initial aqueous sample for the direct procedure, and 2.5-15 micro g/100 ml of sample when the extraction system was used. Water samples from the river Kharoon and soil samples were analyzed by the standard method and by the proposed method: correlation of the two methods was 0.986 and 0.99 for the river and for the soil samples respectively. The extraction method is advantageous because it lowers the detection limit by the concentration effect. (Collier-IVI)