An extractive spectrophotometric method for the determination of nitrite using fluorescein amine isomer I

A sensitive spectrophotometric method for the determination of nitrite usin g fluorescein amine isomer I is described. The method is based on the forma tion of azido derivative of fluorescein amine isomer I, which is selectivel y extracted into 20% iso amyl alcohol in toluene and is stripped to aqueous phase using NaOH. Formation of the azido derivative depends on nitrite con centration and the system obeys Beer's law in the range 0-0.4 ppm of nitrit e at 495 nn. The molar absorptivity of the colour system is 6.67 x 10(4) L, mol(-1) cm(-1) with a relative standard deviation of 3% for 10 determinati ons at 1 mu g of nitrite, The proposed method is successfully applied for t he determination of nitrite and nitrate in soil, water and radiator coolant sample, NO2 gas in a laboratory fume cupboard is determined after fixing i t as nitrite in sodium arsenite absorber solution.