Single Sweep Polarographic Determination of Trace Nitrite in Ferrous and Ascorbic Acid Medium

Abstract

The (FeNO)²⁺ complex can be formed in a solution that contains ferrous ion (ammonium ferrous sulfate), nitrite (sodium nitrite) and ascorbic acid. With a dropping mercury electrode, this complex has a catalytic wave at -0.58V which can be used for the determination of trace nitrite in the range of 1×10^-7 to 4×10^-4M with the detection limit of 5×10^-8M. The function of ascorbic acid is to reduce NO₂^- to NO quantitatively for complete formation of the electroactive complex. The mechanism of the electrode process has been studied by linear sweep polarography, direct current polarography, cyclic voltammetry and spectrophotometry.