Electrochemical Biosensors Based on Enzymatic Reactors Filled by Various Types of Silica and Amalgam Powders for Measurements in Flow Systems
Abstract
Two enzymatic biosensors with amalgam powder reactors and twelve enzymatic biosensors with various silica powder reactors were fabricated and tested in this work. The enzymatic reactors based on silver amalgam powder provide high sensitivity and they are convenient for faster flow rates.
Experiments with six silica materials showed that mesoporous silica SBA-15 was the best one in terms of covering by enzymes, sensitivity and lifetime of biosensors. The current response of the SBA15-glucose oxidase (GOx) sensor started to decrease only after 200 day testing and after 406 days the peak current was still 35.9% of the initial value.
The used amalgam tubular detector in a flow system allowed working at highly negative potentials, which significantly increased the sensitivity of determinations. Statistical results of parallel measurement of model solutions with the fabricated biosensors show their high accuracy (RSD=0.28-1.81%) and sensitivity (6.2-14.3 mu mol L-1).
The proposed SBA15-GOx biosensor was successfully used for determination of glucose in commercial honey.