Review on nanomaterials-enabled electrochemical sensors for ascorbic acid detection.

This review (with 307 refs.) addresses the recent advances in electrochemical nonenzymatic ascorbic acid (AA) sensors using various nanomaterials as sensing elements. In general, nanomaterials have paved the way for a novel and advanced sensing device due to their unique physical and chemical properties. AA sensors based on noble metals, their nanoparticles, transition metals/metal nanoparticles, alloys/bimetallic nanoparticles, conducting polymers and carbon nanomaterials have been reviewed. Also, there has been a focus on describing the details of many significant articles explaining the design of sensors and utilities of the prepared sensors, so that readers might get the principles behind such devices and relevant detection strategies. Finally, the challenges and prospects for the application of nanomaterials-enabled electrochemical sensors for AA analysis have also been incorporated.

Fabrication of Highly Sensitive Nonenzymatic Electrochemical H2O2 Sensor Based on Pt Nanoparticles Anchored Reduced Graphene Oxide.

A highly sensitive nonenzymatic hydrogen peroxide (H2O2) sensor was fabricated using platinum nanoparticles decorated reduced graphene oxide (Pt/rGO) nanocomposite. The Pt/rGO nanocomposite was prepared by single-step chemical reduction method. Nanocomposite was characterized by various analytical techniques including Raman spectroscopy, X-ray diffraction, field emission scanning electron microscope and high-resolution transmission electron microscopy. Screen printed electrodes (SPEs) were fabricated and the nanocomposite was cast on the working area of the SPE. Cyclic voltammetry and amperometry demonstrated that the Pt/rGO/SPE displayed much higher electrocatalytic activity towards the reduction of H2O2 than the other modified electrodes. The sensor exhibited wide linear detection range (from 10 µM to 8 mM), very high sensitivity of 1848 µA mM-1 cm-2 and a lower limit of detection of 0.06 µM. The excellent performance of Pt/rGO/SPE sensor were attributed to the reduced graphene oxide being used as an effective matrix to load a number of Pt nanoparticles and the synergistic amplification effect of the two kinds of nanomaterials. Moreover, the sensor showed remarkable features such as good reproducibility, repeatability, long-term stability, and selectivity.

Electrochemical nonenzymatic sensing of glucose using advanced nanomaterials.

An overview (with 376 refs.) is given here on the current state of methods for electrochemical sensing of glucose based on the use of advanced nanomaterials. An introduction into the field covers aspects of enzyme based sensing versus nonenzymatic sensing using nanomaterials. The next chapter cover the most commonly used nanomaterials for use in such sensors, with sections on uses of noble metals, transition metals, metal oxides, metal hydroxides, and metal sulfides, on bimetallic nanoparticles and alloys, and on other composites. A further section treats electrodes based on the use of carbon nanomaterials (with subsections on carbon nanotubes, on graphene, graphene oxide and carbon dots, and on other carbonaceous nanomaterials. The mechanisms for electro-catalysis are also discussed, and several Tables are given where the performance of sensors is being compared. Finally, the review addresses merits and limitations (such as the frequent need for working in strongly etching alkaline solutions and the need for diluting samples because sensors often have analytical ranges that are far below the glucose levels found in blood). We also address market/technology gaps in comparison to commercially available enzymatic sensors. Graphical Abstract Schematic representation of electrochemical nonenzymatic glucose sensing on the nanomaterials modified electrodes. At an applied potential, the nanomaterial-modified electrodes exhibit excellent electrocatalytic activity for direct oxidation of glucose oxidation.