Electrochemical sensors based on binuclear cobalt phthalocyanine/surfactant/ordered mesoporous carbon composite electrode.

A new ordered mesoporous carbon (OMC) composite modified electrode was fabricated for the first time. Binuclear cobalt phthalocyaninehexasulfonate sodium salt (bi-CoPc) can be adsorbed onto didodecyldimethylammonium bromide (DDAB)/OMC film by ion exchange. UV-vis spectroscopy, scanning electron microscopy (SEM) and electrochemical methods were used to characterize the composite film. The cyclic voltammograms demonstrate that the charge transfer of bi-CoPc is promoted by the presence of OMC. Further study indicated that bi-CoPc/DDAB/OMC film is the excellent electrocatalyst for the electrochemical reduction of oxygen in a neutral aqueous solution and hemoglobin (Hb) at lower concentrations. Additionally, as an amperometric 2-mercaptoethanol (2-ME) sensor, this modified electrode shows a wider linear range (2.5 x 10(-6) to 1.4 x 10(-4) M), high sensitivity (16.5 microA mM(-1)) and low detection limit of 0.6 microM (S/N=3). All these confirm the fact that the new composite film may have wide potential applications in biofuel cells, biological and environmental sensors.

The control of phthalocyanine properties through nitro-group electronic effect.

The UV-vis spectra of peripherally substituted tetranitrometallophthalocyanines (TNMPcs) 1a-1d and non-peripherally substituted TNMPcs 2a-2d were investigated. In comparison of 1a with 2a, there is the only difference in the substitution position of nitro-groups. The structural diversity of 1a and 2a resulted in different electronic effects of nitro-group on Pc rings, which caused them have two kinds of Q bands. The Q band in the UV-vis spectra of 1a-1d was split into two peaks, which were obviously influenced by temperature, while no split was observed in the Q band of 2a-2d. We can draw a conclusion that tuning nitro-group electronic effect is an important approach for controlling the properties of Pcs.

[Library search of UV spectra of organic environmental pollutants by temperature-constrained cascade-correlation networks].

A temperature-constrained cascade-correlation network (TCCCN) was used to identify ultraviolet (UV) spectra of organic environmental pollutants. Library search for UV spectra is more difficult than that for infrared (IR) spectra, because the UV spectra overlap more severely than IR spectra. Besides, drift and noise in the measurement will have significant effect on UV library spectra search. Therefore, neural networks with fuzzy output should be a better alternative for the library search. The TCCCN is different from the commonly used BP networks in architecture. The processing units in the TCCCN are connected in a cascade mode, and a temperature constraint is introduced. Therefore, the TCCCN can reduce overtraining and fast training speed. TCCCN was used for library search of UV spectra in the present work and the effects of network parameters and noise were investigated. Results showed that better results were obtained with the TCCCN than with conventional correlation method.