Nanostructured Polyoxometalate-Based Heterogeneous Electrode Materials for Electrochemical Sensing of Glucose

Abstract

We exploited a tactic to obtain a low-cost, highefficiency, pollution-free, and stable nonenzymatic polyoxometalatebased heterogeneous electrode material for electrochemical sensing of glucose. It is first followed by the countercation exchange of K 2 Na 8 [Cu 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] (CuPOM) using cesium chloride to prepare an insoluble CuPOM (Cs-CuPOM), which exhibits a uniform and perfect claviform shape with smooth surface. Further, it was mixed with graphite powder to prepare Cs-CuPOM-modified carbon paste electrode (Cs-CuPOM/CPE) with the Cs-CuPOM content between 15% and 50% in weight. This obtained electrode material Cs-CuPOM shows a better electrochemical sensor activity than Cs-MnPOM, Cs-FePOM, and other reported POM-based electrode materials for glucose oxidation on account of their quicker electron transfer kinetics, which also exhibits conspicuous characteristics with a wide linear range of 5−1500 μM. It also possesses a high sensitivity of 16.3 A M −1 cm −2 and a low limit of detection (LOD) of 0.99 × 10 −6 M at the signal-to-noise ratio of 3. The conspicuous sensing feature, low cost, and liable synthetic method can make Cs-CuPOM a promising candidate for the exploitation of a preeminent glucose sensor.

Advances in polyoxometalate-based electrochemical sensors in the last three years

“…A significant number of POM-based ECSs are mainly based on the redox reactions of target substances. 46,52,61–63 Specifically, when the analyte is in contact with a POM-based ECS, if the target is reductive, it will lose electrons on the electrode surface and be oxidized. Conversely, if the target substance is oxidizing, it will gain electrons on the electrode surface and be reduced.…”

“…At present, POM-based redox ECSs have been applied in detecting organic pollutants, biomolecules, heavy metal ions, etc. 46,52,61–63,65–68 However, there are also some challenges and limitations that need to be addressed. Among these are the issues of excessive power consumption and the susceptibility to environmental factors like temperature, humidity, and air flow, which may lead to a high false positive rate and thus limit the application range.…”