PORPHYRIN DIMER AS NEUTRAL IONOPHORE FOR A BERBERINESENSITIVE POTENTIOMETRIC SENSOR

The synthesis of a dimer of porphyrin linked by flexible alkoxyl chains and its application as neutral ionophore for a berberine-sensitive potentiometric sensor were described. The porphyrin dimer based sensor shows a linear response towards berberine in the range 1.2 × 10-7–5.0 ×10-3 mol L-1, with a pH range from 3.7 to 11.2, a fast response time of 10 s and a slope of 65.5 ± 2.5 mV/dec. The proposed electrode exhibits different selectivity behavior compared with the electrode based on classical cation exchanger. As an electroactive material, porphyrin dimer shows better potentiometric response characteristics comparing to porphyrin monomer or metalloporphyrin. The effects of solvent mediator have been studied and the experimental conditions optimized. The interaction between BE+ and porphyrin dimer was investigated using UV-VIS spectrophotometry. The electrode can be used in the direct assay of BE in pharmaceutical preparations with satisfactory results.