ELECTROCHEMICAL AND SPECTROPHOTOMETRIC STUDY OF THE BEHAVIOR OF ELECTROPOLYMERIZED NICKEL PORPHYRIN FILMS IN THE DETERMINATION OF NITRIC-OXIDE IN SOLUTION

We describe in this paper an electrochemical and spectrophotometric st udy of the behavior of an electropolymerized nickel porphyrin film as a sensor for the determination of nitric oxide (NO) in aqueous solutio n. Our results show that the anodic oxidation of NO at the modified el ectrode may not be the result of a catalytic effect induced by the por phyrinic complex. However, the current (measured by differential pulse amperometry) and calculated NO concentration showed a linear relation ship in the range 15 nM-6 mu M in aerobic phosphate buffer solution (p H 7.4). These results provide a fruitful example of calibration of suc h electrochemical sensors for the selective detection of NO with a cal culated detection limit, at a signal-to-noise ratio of three, equal to 1.5 nM.