Highly sensitive determination of hydrogen peroxide and peroxidase with tetrathiafulvalene-based electrodes and the application in immunosensing.
Redox mediators enable an efficient electron transfer between redox enzymes and the electrochemical surface of amperometric sensors. A stable and highly sensitive signal was obtained using a tetrathiafulvalene (TTF)-modified graphite electrode. In the presence of horseradish peroxidase (HRP), hydrogen peroxide (H2O2) was monitored with a detection limit of 7 nM at a potential of +20 mV versus a saturated calomel electrode (SCE). With a constant concentration of H2O2, the detection limit for HRP was found to be 150 pM. The accuracy of consecutive measurement of HRP in flow-through systems was improved by short-time polarizing the TTF-modified graphite electrode at +100 mV versus Ag/AgCl/3 M KCl. Using the TTF-modified graphite electrode in an immuno-sandwich approach, rabbit-immunoglobulin G was monitored in the range 5-100 ng/ml.
Wendzinski
F
F
Institut für Chemo- und Biosensorik, Münster, Germany.
Gründig
B
B
Renneberg
R
R
Spener
F
F
D000818:Animals; D015374:Biosensing Techniques; D006735:Horseradish Peroxidase / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D011817:Rabbits; D013696:Temperature
D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase