Photo-switchable Enzyme Sensors. Photoinduced Potentiometrie Response of Glassy Carbon Electrode Coated with Poly (vinyl chloride) Membrane Entrapping Spirobenzopyran Derivative or Enzyme Dual Membrane

The photoinduced potential change of the spirobenzopyran derivative (l′-p-nitrobenzyl-3′,3′-dimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-indoline]) doped poly (vinyl chloride) (PVC) membrane-coated glassy carbon (GC) electrode was drastically suppressed by the kind and the amount of the cationic sites in the membrane. But the photoresponse of the membrane potential was enhanced by the kind and the amount of appropriate lipophilic anionic sites in the membrane. More than 380 mM potential change was induced with a response time of ca. 1 min, especially in the acidic region. The magnitude of the membrane potential change across the spirobenzopyran doped PVC membrane which contains sodium tetrakis[3,5-bis)trifluoromethyl)phenyl] borate (TFPB) as an ion exchanger, depended upon the concentration of organic amines in the aqueous solution adjacent to the surface of the membrane. L-Histidine and L-tyrosine sensors were prepared by coating the surface of TFPB doped PVC membrane with L-histidine decarboxylase and L-tyrosine decarboxylase, respectively. Photo-switchable creatinine sensor was fabricated by use of creatinine deiminase modified nonactin doped PVC membrane-coated GC electrode.