ABSTRACT
Aim To establish a simple, rapid and accurate electroanalytical method for water soluble porphyrin meso-tetrakis-(4-sulfonatophenyl) porphyrin (TPPS4);to clarify the reaction between water soluble porphyrins and bovine serum albumin (BSA);and to determine the interaction of TPPS4 with BSA in the absence of presence of cyclodextrins (CDs) , separately. Methods Three methods including LSV,UV spectroscopy and fluorescence spectroscopy bad been employed to the relevant experiments. The way of employing three methods at the same time could make the experiment results more reliable. Results In the supporting electrolyte of NaH2 PO4-Na2 HPO4 ( pH 7. 18 ), a sensitive reduction peak of TPPS4 was found by linear sweep voltammetry (LSV), the peak potential (Ep) was-0. 70 V (vs SCE). The relationship between the second derivative peak of LSV (ip") and the concentration of TPPS4 was linear from 1.0 × 10-7mol·L-1 to 1.0 × 10-5mol· L-1,the square of correlation coefficients (r2) were 0. 998 3 and 0. 999 3, respectively. The relative standard deviation (RSD) was 0. 56% ( n = 5 ). The mean recovery of TPPS4 was 99.59％. In NH4C1-NH3· H2O buffers (pH 9.05), it was proved that BSA and TPPS4 could interact with each other and form 1:1 TPPS4-BSA supramolecular system. Moreover, the interaction between TPPS4 and BSA had been investigated by adding cyclodextrins (CDs). The interaction of TPPS4 with BSA was facilitated both by hydroxypropyl-β-CD (HP-3-CD) and sulforbutylether-β-CD (SBE-3-CD). Conclusion An electroanalytical method for TPPS4 has been established by LSV. The porphyrin drugs included by CDs could react with protein existing inside the human body easier. The consequences of this article also show that CDs will play important role in controlling and releasing the porphyrin drugs.
ABSTRACT
The Polarographic and voltammetric behavior of Cd (Ⅱ)-meso-tetrakis(p-sulfophenyl)prophyrin (TPPS4） complex was defined and the cyclic voltammetric peak was obtained at 1.200 V (vs. SCE) in 0.3 mol/L NaoH solution. The characteristics of the peak have been examined in detail and the experimental results prove that the peak has adsorption properties. In addition to the number of electrons transferred in the reaction and the complex ratio, the stability const ant (β=1.19×107) was calculated. The peak current was proportional to the concentration of Cd (Ⅱ) over the rang 3×10－7～1×10－5 mol/L and the limit of detection was 6×10－8 mol/L. Furthermore a possible mechanism was proposed for the reduction of the complex.