STUDIES OF THE INTERACTION BETWEEN METALLOPORPHYRIN FILMS AND PHENOLSIN A PRECONCENTRATION TYPE SENSOR

Metalloporphyrins have been used as sensors to detect phenols. We desc ribe several experiments that indicate that the increment of current r esponse is due to a preconcentration effect of the phenolic analyte in the modifying layer. The aromatic structure seems to be crucial to ac hieve this goal, indicating pi-pi interaction. The electrical response to phenols of a variety of poly[M-(PPIX)I films, M = Ni-II, Co-II and Cu-II was measured suggesting an axial ligand-metalloporphyrin intera ction. The IR spectras of p-nitrophenol with and without porphyrins we re obtained showing a gradual decrease of the signal at 1205.6 cm(-1), corresponding to C-O stretching acid the presence of two new peaks (1 236.7, 1167.4cm(-1)). Further signal at 1345 cm(-1) corresponding to s ymmetric (ArNO2) N-O stretching, remains unchanged. Therefore, these r esults indicate that the -C-OH the OH group is involved in the binding .