DETERMINATION OF NITRATE AND NITRITE IN TAP WATER AND VEGETABLES BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A method is presented for the simultaneous determination of nitrate an d nitrite by high performance liquid chromatography (HPLC) with an ani on exchange (Partisil SAX) column, a 0.030 M potassium dihydrogen orth ophosphate/phosphoric acid buffer of pH 3.5 mobile phase and UV detect or. Without using a preconcentration system the detection limits are 0 .2 ng for nitrate and 1 ng for nitrite. A suitable extraction procedur e has been established for its application to the analysis of tap wate r, lettuce and apple tree leaves. The reproducibility of the method, c alculated as the relative standard deviations in the optimum range, is always less than 2% for nitrates and 5% for nitrites.