Glassy Carbon Electrode Modified with Nickel (II) Tetrasulfophtalocyanine Films and its Behavior as Amperometric Sensor for Nitrite

In this work, a modification of a glassy carbon electrode with a film of Nickel (II) tetrasulfophtalocyanine (f-NiTSPc) was done, which was obtained by a continuous potential cycling in aqueous solution. It was found that a modified electrode with f-Ni(II) TSPc increases its activity versus nitrite oxidation, in comparison to the bare glassy carbon electrode (GC) and the monomer multilayers of this complex (m-Ni(II) TSPc). Its activity was studied versus different pH, and it was found that the better conditions for nitrite oxidation were at pH 7.2. At this pH kinetic calculations were done, finding that it is a diffusional process with a one-electron transference and a Tafel-slope value of 59 mV/dec, postulating a possible reaction mechanism. Finally, the electrode behavior was studied as possible amperometric sensor for nitrite, obtaining and calculating its analytical parameters such as accuracy, exactitude, detection and quantification limits, being a good method for nitrite quantification in aqueous solution.