Electrocatalytic modified electrodes with transition metal azamacrocycles and other complexes for the detection of sulfur and nitrogen oxoanions

Modified electrodes with transition metal phenantrolines, phthalocyanines, porphyrins and other complexes where the metal center is a transition metal have been widely studied because they show highly activity toward the oxidation and reduction of several analytes. One of the most interesting applications of these modified electrodes is the determination of oxoanions in waste water, food and beverages. In fact, they have been used to detect nitrite, nitrate, sulfite, and other pollutants or traces with low limit detection and in some cases; specificity. On the other hand, it is interesting that these modified electrodes can be designed for desirable purposes by changing the metal center, modifying the ligand, or changing the electrolyte. There are some cases in which the position of a substituent on the ligand can drastically change its activity. The modified electrodes are been used as supramolecular assemblies, as electroactive films or as composites of different layers adsorbed on the surface. This brief review shows the last decade's studies on the detection of sulfur and nitrogen oxoanions using electrodes modified with metal transition complexes.