The Research On The Properperties Of Porphyrins And Its Application In Chemically Modified Electrodes

Porphyrin is a general term of a class of macrocyclic compounds with substituting groups at the outside ring. When two portons inside the ring are displaced by the metal ion, metalloporphyrins is abtained. Since the porphyrin and its metal complexes exhibit a special structure and properties, they play an important role in medicine, biochemistry, material science and analytical chemistry and other fields.The synthesis of porphyrin always started from tetraphenylporphyrin, so the research on the tetraphenylporphyrin is particularly important. In this thesis, we have done some works in this field and the main results are expressed as follows:1. Study on the spectral and electrochemical properties of tetraphenylporphyrin and its derivativesThe spectroscopic and electrochemical properties of tetraphenylporphyrin and its derivatives were studies by UV-vis, fluorescence, cyclic voltammetry and the influences of different substitutes on their properties were discussed and the variation rules were summarized.2.Study on the application of trans-diamino-tetraphenylporphyrin (trans-dA-TPP) as a voltammetric sensor of mercuryThe chemical modified electrode was prepared by simple and rapid electroless dipping procedure. The surface morphology of the chemical modified electrode was characterized by atomic force microscopy (AFM). The electrochemical properties of this trans-dA-TPP/GCE were studied using cyclic voltammetry. The trans-dA-TPP /GCE was used as a voltammetric sensor for determination of trace Hg2+ in acetate-acetic acid buffer (pH 3.6) using differential pulse anodic stripping voltammetry. Under the optimal experimental conditions, the stripping peak current was linear with the Hg2+ concentration in the range of 1.0×10-8 to 1.0×10-6mol L-1 with a detection limit of 1.0×10-9 mol L-1. The proposed method was applied to the determination of Hg2+in real samples and the results are satisfactory. 3. Study on the application of nickel-tetraphenylporphyrin (Ni-TPP) as a voltammetric sensor of guanineA novel voltammetric sensor of guanine was fabricated by nickel tetraphenylporphyrin. The chemical modified electrode has been utilized for the electrochemical oxidation of guanine in phosphate buffer solution. Under the optimal experimental conditions, the peak currents of guanine were proportional to the concentration of guanine in the range of 6.0×10-7 to 5.0×10-5 mol L-1, with a detecting limit of 1.0×10-7 mol·L-1.