Abstract
A simple and rapid method for the determination of nitrite and nitrate ions in ambient waters was developed by high performance liquid chromatography. Porous silica type anion exchange packing material (Partisil-10 SAX) was useful for the separation of these ions. Nitrite and nitrate ions were eluted with 0.005 M buffer solution of KH2PO4-Na2HPO4 (pH 6.4) and detected at UV 205 nm. The height equivalent to a theoretical plate for nitrate ion was 0.04 mm and peak resolution between nitrite and nitrate ions was about 5 for the column of 25 cm × 4.6 mm i.d. The calibration curves were linear up to 50 ng. One thousand ppm of phosphate ion, sulfate ion and 100 ppm of anionic surface active agent did not interfere with the determination, while more than (100200) ppm of chloride ion did. Several samples of river water were analysed by this method and (0.63.6) ppm of nitrite and (4.420) ppm of nitrate ions were found. The analytical time for one sample was about ten min. In the case of sea water, the interference caused by chloride ion was removed by dissolving 1 g of sodium chloride in 11 of eluent to makethe concentration of 0.017 M. The recovery of nitrate ion (2 ppm) added to standard sea water was 97.4 % and the coefficient of variation was 2.3 %. Several samples of sea water were found to contain (0.20 0.76) ppm of nitrite and (0.713.49) ppm of nitrate ions by this method.
