Yuan R, Chai Y Q, Shen G L, Yu R Q
Department of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082 People's Republic of China.
Talanta. 1993 Aug;40(8):1255-9. doi: 10.1016/0039-9140(93)80195-w.
A chemically modified platinum electrode with coated poly[tetra(4-aminophenyl)porphyrin] has been used as a potentiometric pH sensor. It gives a linear response over the pH range 1.5-13.7 with a slope of 55 mV/pH (at 20 degrees ). The sensor has fair resistance to erosion of hydrofluoric acid and to interference of a coexisting redox couple. The sensor can be used for pH determination and end-point indication for potentiometric titration of hydrofluoric acid with sodium hydroxide. The a.c. impedance of the polymer membrane has also been studied.
