Determination of nitrite and nitrate ions by ion-pair chromatography with C₃₀ as a stationary phase

Abstract

A method for the determination of nitrite and nitrate ions has been developed for ion-pair chromatography (RP-HPLC) with a new C₃₀ column, coupled with an UV detector at 210. A phosphate buffer (pH 6.0) containing 2 mM tetrabutylammonium (TBA-OH) in 10 (v/v)% acetonitrile was used as an optimal mobile phase for the separation of six anions (NO₂^-, Br^-, NO₃^-, SeO₃^2-, SeO₄^2- and I^-). The six anions were efficiently separated within 25. Especially, the calibration curves of the nitrite and nitrate ions, to 50.0 μg/ml from 0.05 μg/ml, were linear with excellent correlation coefficients of more than 0.999 and a relative standard deviation of under 1% from 10 repeated measurements; and limits of detection were 5 ng/ml (S/N=3).