Determination of sulfite by flow injection analysis using a poly[Ni-(protoporphyrin IX)] chemically modified electrode

A new method for quantification of both free and total SO2 is described. Poly[Ni-(protoporphyrin IX)] (NiPPIX) film at submonolayer-level-modified glassy carbon electrodes showed an important catalytic effect for the oxidation of SO2. This modified electrode is an useful tool in chemical analysis when it is incorporated to an amperometric detector in a flow or in a stirred system. The method gives a linear range up to 9.0 μg ml−1 and a detection limit of 0.15 μg ml−1 for SO2. The described method is simple and non-expensive. e coating is highly stable under hydrodynamic conditions in the flow cell.