Chemiluminescence flow biosensor for glucose using Mg-Al carbonate layered double hydroxides as catalysts and buffer solutions

In this work, serving as supports in immobilizing luminol reagent, catalysts of luminol chemiluminescence (CL), and buffer solutions for the CL reaction, Mg-Al-CO3 layered double hydroxides (LDHs) were found to trigger luminol CL in weak acid solutions (pH 5.8). The silica sol–gel with glucose oxidase and horseradish peroxidase was immobilized in the first half of the inside surface of a clear quartz tube, and luminol-hybrid Mg-Al-CO3 LDHs were packed in the second half. Therefore, a novel CL flow-through biosensor for glucose was constructed in weak acid solutions. The CL intensity was linear with glucose concentration in the range of 0.005–1.0 mM, and the detection limit for glucose (S/N=3) was 0.1 μM. The proposed biosensor exhibited excellent stability, high reproducibility and high selectivity for the determination of glucose and has been successfully applied to determine glucose in human plasma samples with satisfactory results. The success of this work has broken the bottleneck of the pH incompatibility between luminol CL and enzyme activity.

► Mg-Al-CO3 LDHs served as supports in immobilizing luminol, catalysts of luminol CL and buffer solutions.
► Glucose oxidase, horseradish peroxidase and luminol were immobilized in one column.
► A stronger CL intensity of the luminol system can emit in weak acid solutions.
► The CL flow-through biosensor showed excellent stability, high reproducibility and simple procedures.