Development of POF flow-injection for spectrophotometric determination of nitrite

A POF flow injection cell is developed to determine nitrite in aqueous based on spectrophotometric method. The jacket of the POF is used as a chamber cell with 10mm core as pathlength. The direct absorbance spectrophometric principle is applied in this work and a range of 400nm to 650nm wavelengths were selected as the nitrite absorption region. Sample of nitrite concentration from 0.2156ppm to 6.9ppm are tested by using syringe pumped into the cell. Colorimetrie of the sample is produced by greiss reagent method. The method based on reaction of nitrite with sulphanilamide acid and N-l-napthylamine which caused pink colour azo dye proportional to the nitrite concentration present in the aqueous sample. The result shows that peak wavelength absorbance at 545nm with standard deviation range from 0.0004 to 0.0107 and precision from 0.5% to 0.03%. Meanwhile, limit of quantitation and limit of detection are 0.158ppm and 0.0052ppm, respectively. These results indicate satisfied parameters for analytical analysis and sensitivity was moderate.