A. Mazloomifar - Islamic Azad University branch Shahre-Rey , tehran, Iran
A. Pourjahan - Islamic Azad University branch Shahre-Rey, tehran, Iran

Tetraethylammonium (TEA) is a quaternary ammonium cation consisting of four ethyl groups attached to a central nitrogen atom .In addition of Tetraethylammonium bromide to an aqueous solution of a sodium salt may cause it to precipitate from water as the Tetraethylammonium salt. A simple, fast, sensitive and accurate (reversed-phase) ion-pair HPLC method for determination of nitrite and nitrate in waters has been developed.This method was applied for the simultaneous determination of nitrite and nitrate in drinking water .Separations were accomplished in less than 7 min using a reversed-phase C8 column (4.6mm×150mm, 5µm particle size) with a mobile phase containing 83% ion-pair reagent Tetraethylammonium bromide (TEA-Br) and sodium phosphate buffer at pH 2 and 17% acetonitrile (flow rate, 0.4 mL/min). UV light absorption responses at 222 nm has been optimized.