| Scope and method of study. This study is motivated by the fact that solutions of certain metal phthalocyanines are among the best rate modifiers in luminol chemilumin-escence in the presence of carbon dioxide, and in the absence of other added oxidant. This study investigates the electropolymerization of some metal phthalo-ocyanine complexes on glassy carbon and indium tin oxide surfaces. The complexes used in this study include copper, cobalt, and zine(II)-4, 9, 16, 23-tetraminophthalocyanine. The immobilization of these complexes by electropolymerization offers an attractive and effective avenue for reproducible surface modification. The modified surfaces, in the presence of carbon dioixide and high pH solutions, are characterized by electrochemical methods such as cyclic voltammetry. Once characterized, the modified surfaces are evaluated as potential rate modifiers in luminol chemiluminescence in the presence of carbon dioxide.;Findings and conclusions. All of the electropolymerized thin films show quasireversible thin layer electrochemistry. In the luminol chemiluminescence studies involving carbon dioxide and solutions of the rate modifier, ZnPc is the best, followed by CoPc, and then CuPc. Initially it was expected that when using the solid thin films of the complexes, the aforementioned series would follow the same pattern. However, in using the films as rate modifiers, CuTAPc is the best, followed by ZnTAPc, and then CoTAPc. The thin films of CuTAPc are more compact, and have more monolayers than both ZnTAPc, and CoTAPc. Surfaces that have many monolayers help to give larger signals than surfaces that have only a single monolayer or several layers. Since CuTAPc contains a greater number of monolayers, than CoTAPc, and ZnTAPc it should provide a greater signal. These observations point to the fact that CuTAPc thin films should preferably be used in the luminol chemiluminescence system in the presence of carbon dioxide since these thin films provide more monolayers and there are insignificant changes in the thin film structure when it is exposed to a high pH solution. |
