On-line flow injection analysis using gold particle modified carbon electrode amperometric detection for real-time determination of glucose in immobilized enzyme hydrolysate of waste bamboo chopsticks

Dual on-line flow injection analysis (FIA) systems were coupled to an immobilized enzyme reactor. The primary system was detected by amperometric enzyme electrode through a specifically designed three-electrode flow cell and a stopped-flow sampling and injection device to perform the successive real-time determination of glucose in the enzyme hydrolysate of waste bamboo chopsticks fibers. The secondary system was established via high-performance liquid chromatography-refractive index detection for comparison purpose. The novel enzyme electrode was made by chemically bonding both the redox mediator ferrocenecarboxaldehyde and glucose oxidase to a gold-particles modified pencil lead carbon electrode that possessed the widest linear standard calibration concentration range of 0–39.0 mM (r2 = 0.9956), a limit of detection of 7.8 μM, fast response time of 5 s, and a detection sensitivity of 2212 nA mM−1. The electrode was usable more than 50 days. The greatest amount of glucose produced from hydrolysis was 0.46 mM at 32 h. Interference from mannose and galactose was 7% and 5%, respectively, that was neglected by their small concentration in hydrolysate. The on-line FIA of amperometric enzyme electrode detection has good analytical precision (RSD 2.2–4.5%) and accuracy (94.4–97.7%) for the real-time glucose determination. The statistical analysis shows that no systematic error exists between the quantitative results of two FIA systems.