Study On The Dissolved Oxygen Detecting And The Preparation Iron Porphyrin LB Films Electrode

Oxygen detecting has been widely applied in in the industrial control, environmental monitoring, medical and people’s daily life. Thus developing rapid, sensitive and efficient oxygen detecting method and technology is of great significance. Heme is the essential substances in the human body and mammal body blood, which is mainly responsible for transporting and transferring the body oxygen. Hemin(porphyrins) is the synthesized chloride of heme which is similar to heme.it can also detecting oxygen in some cases. And the hemin modified electrodes are playing an important role in detecting oxygen.In this paper, iron porphyrins LB film was prepared and a series of different conditions of heat treatment were used to optimize its electrochemical performance. The UV-visible absorption spectrum and infrared spectrum was obtained. The infrared peaks was assigned. Use the three-electrode system to character the optimized iron porphyrins LB films which examines the properties in detecting the different concentration of dissolved oxygen in KCl solution to imitate animal body in-situ test. Then the electrode was examined in KCl solution containing different concentrations of iron porphyrins to evaluate the influence on detecting oxygen.The results showed that iron porphyrin molecules and ITO glass electrode combined tightly and orderly after the optimized conditions of different heat treatment which causing B band UV-vis absorption spectrum blue shift and Q band absorption peak decreases. The number of the infrared absorption spectrum peaks changed as the heat treatment temperature and time changing regularity. The infrared peaks was at most when it was heat treatment at 60°C for 3 hours. Selecting the sample with the fitted treatment to detect the different concentration dissolved oxygen in KCl, it indicated that cycle voltammogram curve increased regularly change with the linear change of the concentration of dissolved oxygen. The CV curve can be separate from each other and response fast. The iron porphyrins on the electrode form the polymer with the iron porphyrins in the solution by the axial coordination when the solution containing iron porphyrins. The discrimination and the response rate reduced. The UV-visible absorption spectrum showed that the oxygen would be captured by the iron porphyrins on the electrode then combining the dissociative iron porphyrins formed the sandwich structure polymer.Further experiments showed that the electrode prepared by the LB technology had a better discrimination and response faster than the electrode prepared by the chemical deposition method, which clarified the LB iron porphyrins films had obvious advantage in detecting dissolved oxygen.