Potentiometric Urea Biosensor Based on Carbon Nanotubes and Polyion Complex Film.
Enzymatic electrode for a potentiometric urea sensor was prepared by sequential coating of carbon nanotube (CNT), urease (Urs) and polyion complex (mixture of poly-L-lysine hydrobromide and poly (sodium 4-styrenesulfonate), PIC) on an ITO glass. The prepared electrode (ITO/CNT/Urs/PIC) was characterized by potentiometric measurements at different urea concentrations in Tris-HCI buffer (pH 7.0). The potentiometric response of the electrode was linear in the range of 1 x 10(-5) to 3 x 10(-3) M with a correlation coefficient of 0.999 and a sensitivity of 59.1 mV/decade. It was found that the addition of CNT caused considerable improvement of the sensitivity of the electrode to urea. The response time was approximately 60-90 s. A half of the initial sensitivity was retained for 15-17 d at room temperature.
Linh Thi My
LT
Nguyen
Hyon Hee
HH
Yoon
D015374:Biosensing Techniques / Q000295:instrumentation*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D011199:Potentiometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013451:Sulfonic Acids / Q000737:chemistry*; D014508:Urea / Q000032:analysis* / Q000737:chemistry; D014510:Urease / Q000737:chemistry*
D004800:Enzymes, Immobilized; D007477:Ions; D037742:Nanotubes, Carbon; D011108:Polymers; D013451:Sulfonic Acids; D014508:Urea; D014510:Urease; C077114:styrenesulfonic acid polymer