Acid stability of carbon paste enzyme electrodes.
This note reports on the unusual protection of several enzymes against harsh pH conditions provided by carbon paste electrodes. Both glucose oxidase and polyphenol oxidase carbon paste amperometric biosensors display a remarkable resistance to acid deactivation compared to conventional biosensors prepared by electropolymeric entrapment of enzymes. For example, the carbon paste enzyme electrodes fully retain their activity upon stressing in strongly acidic conditions (pH approximately 2.0-2.5) for prolonged periods, where conventional (polymer-based) biosensors rapidly lose most of their response. Such unusual acid stability of carbon paste enzyme electrodes is attributed to the "pH memory" of enzymes in the hydrophobic paste environment, to the barrier to hydronium ions provided by the pasting liquid and to decreased conformational mobility.
Wang
Joseph
J
The Biodesign Institute, Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287-5801, USA. joseph.wang@asu.edu
Musameh
Mustafa
M
Mo
Jian-Wei
JW
D000143:Acids; D015374:Biosensing Techniques; D002244:Carbon / Q000737:chemistry*; D004566:Electrodes
D000143:Acids; D002244:Carbon