SPECTROPHOTOMETRIC DETERMINATION OF TRACES OF NITRITE WITH RHODAMINE-6-G

A simple and highly selective spectrophotometric method is described f or the determination of nitrite. The method is based on the measuremen t of decrease in absorbance at 525 nm of rhodamine 6 G in sulphuric ac id medium. The decrease in absorbance is instantaneous on addition of nitrite and remains stable for 2 h. Linear calibration graph passing t hrough the origin was obtained in the range 0.01-0.6 mug/ml nitrite. T he method is free from interference of Cu2+, Fe3+ and SO32- which norm ally interfere in other procedures. The method was applied successfull y to the determination of nitrite in well and sea water samples and in KNO3, NaNO3, table salt, sugar and milk powder samples.