Simulataneous determination of nitrite and nitrate in water using flow-injection biamperometry

Abstract Detection with two polarized platinum wire electrodes is based on the oxidation of iodide by nitrate. The current is proportional to the amount of iodine formed. The injected sample is split in a flow-injection manifold into two segments. One of them is transported through a reductor minicolumn containing copperized cadmium, where reduction of nitrate to nitrate occurs. The effects of interfering species such as Cu(II), Fe(III), Cr(VI) and residual chlorine were examined and procedure for their elimination are proposed. With a sampling of 15 h −1 , detection limits of 40 and 70 γ 1 −1 were obtained for nitrite and nitrate, respectively.

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