A potentiometric acetylcholine microsensor was fabricated by use of a composite film consisting of polyion complex (PIC), which consisted with acetylcholine esterase (AChE), and the electrochemically inactive poly-1-aminopyrrole (iPAPy). The iPAPy-PIC (AChE) composite film on Pt electrode displayed potential response to acetylcholine concentration owing to pH change during the enzymatic reaction, where the product contains weak acid CH3COOH. The sensitivity of the iPAPy-PIC (AChE) electrode clearly demonstrated higher sensitivity with low detection limit (1 × 10-6 mol dm-3) than that of the iPPy-PIC (AChE) electrode of detection limit (1 × 10-5 mol dm-3). The mechanism of increasing the sensitivity of iPAPy-PIC (AChE) electrode was discussed the interaction of -NH2 of iPAPy with CH3 COOH, which would accelerate the dissociation of weak acid CH3COOH.
- Potentiometric acetylcholine sensor
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