Prussian Blue-Based Thin-Layer Flow-Injection Multibiosensor for Simultaneous Determination of Glucose and Lactate

A planar multibiosensor for the simultaneous determination of glucose and lactate is developed by combining the Prussian Blue-based electrocatalyst and the protocol for immobilization of glucose oxidase and lactate oxidase enzymes from solutions with a high content of an organic solvent. High sensitivity coefficients (>80 mA M –1 cm –2 for lactate and >20 mA M –1 cm –2 for glucose) are demonstrated by the multibiosensors operating in the flow-injection mode in a thin-layer measuring cell. The linear range of the analyzed concentration is 1–500 μM for lactate and 5–1000 μM for glucose. A multibiosensor can be used repeatedly (the exhibited operational stability is not less than 100 measurements without the need for recalibration), which allows using it for the analysis of diluted blood samples and blood serum. The electrocatalytic system with a multibiosensor demonstrates performance characteristics that are superior to the commercial analyzers.