A novel method for the spectrophotometric determination of nitrite in water.

A rapid, simple, selective and sensitive method for the spectrophotometric determination of nitrite in water has been developed and optimum reaction conditions along with other analytical parameters have been evaluated. Nitrite reacts with barbituric acid in acidic solution to give the nitroso derivative, violuric acid. At analytical wavelength of 310nm, Beer's law is obeyed over the concentration range 0.00-3.22ppm of nitrite. The molar absorptivity is 15330+/-259.7 (95%) with pooled standard deviation of 355.57 and R.S.D. of 2.32%. As well as the method is sensitive (2.99x10(-3)mug NO(2)cm(-2)) and selective, it tolerates most of the potential interferents. It has been successfully applied to nitrite determination in natural waters by use of a calibration graph with determination limit of 1.66mug NO(2) in 100mL working solution corresponding to minimum 9.5ppb NO(2)-N in water samples. Lower concentrations of nitrite (3.0mug NO(2)/L sample) is precisely analyzed by using the method of dilution with sample, with R.S.D. of lower than 0.5%. The results were compared with standard N-(1-naphtyl)ethylenediamine dihydrochloride method and very good agreement between the data was observed. The method can easily be applied in the field.