Determination of Glucose on Free Enzyme-based Poly(dimethylsiloxane) Microchip

Microfluidic enzyme-based reactor could be used to detect biomolecules with high sensitivity and selectivity. Based on the electrophoretic-mediated microanalysis (EMMA) method, a novel free enzyme-based microchip was developed to detect glucose. Online catalysis reaction of glucose by glucose oxidase was carried out on the chip. The product H2O2 was detected using amperometric method. The working electrode, single carbon fibre cylindrical electrode, was held at a constant potential of +1.4 V versus Ag/AgCl electrode. The results indicated that the peak current had a good linear relationship with glucose concentration in the range of 0.1–20 mM (R = 0.997) with good reproducibility (RSD = 2.02%, n = 10). The detection limit of glucose was 19.8 μM (S/N = 3). This free enzyme-based reactor was easy to fabricate and operate, which showed great potential application in bioanalysis.