The Application Of Novel Nanocomposite Materials In The Electrochemical Sensors

Nanocomposite materials have attracted more and more researchers due to theirspecial structure and good properties. Various methods are used to synthesize them.We have synthesized some composite nanomaterials by the coprecipitation, sol-gel,electrospinning technology and electrical deposition, respectively. New-typeelectrochemical sensors based on these nanocomposite materials are fabricated withcarbon paste electrode (CPE) or glassy carbon eletrode (GCE) by different processes.Many techniques such as XRD, TEM, SEM, EIS, CV and Raman spectra were used tocharacterize the structures and properties of the nanocomposite materials orelectrochemical sensors. The electrochemical sensors were built for determining thesmall biomolecules. Under the optimal condition, the properties of as-fabricatedelectrochemical sensors were investigated. The results show that the nanocompositematerials have good catalytic activities, and satisfactory results are achieved. Specificresults are as follows:1. A novel glucose sensor and H2O2sensor were fabricated based on theperovskite-type LaNi0.6Co0.4O3nanoparticles (LNC)without any adhesive. LNC weresuccessfully synthesized by the sol-gel method, and the structure and morphology ofLNC were characterized by X-ray diffraction spectrum, scanning electronmicroscopy, transmitting electron microscopy and electrochemical impedancespectroscopy. The results demonstrated that LNC exhibited strong electrocatalyticalactivity by cyclic voltammetry and amperometry. In H2O2determination, linearresponse was obtained in the concentration range of0.01M to100M (highsensitivity1812.84μA·mM–1·cm–2) with a detection limit of1.0nM within3s. Inglucose determination, there was the linear region of0.05M to200M (highsensitivity642.78μA·mM–1·cm–2) with a detection limit of8.0nM (S/N=3).Moreover, this prepared sensor was applied to detect glucose and hydrogen peroxidein practical samples with satisfied results. 2. It was reported on a novel nonenzymatic sensor platform for thedetermination of hydrogen peroxide and glucose. It is based on a carbon pasteelectrode that was modified with Co0.4Fe0.6LaO3nanocomposite particle（sCFLs）thatwere synthetized by the sol-gel method. The structure and morphology of CFLs werecharacterized by X-ray diffraction, scanning electron microscopy, and transmissionelectron microscopy. The electrochemical performance of this sensor was evaluatedby cyclic voltammetry and amperometry, and the results demonstrated that it exhibitsstrong electrocatalytical activity towards the oxidation of H2O2and glucose. TheH2O2sensor has a limit of detection as low as2.0nM of H2O2and a linear range thatextends from0.01to800μM. Also, the response to glucose was characterized bytwo analytical ranges of different slope, viz. from0.05–5μM and from5–500μM,with a10nM limit of detection.3. It was reported on a sensor platform for the determination of L-tryptophane. Itis based on a carbon paste electrode that was modified with LaCoO3poriferousnanofibers (LCPFs) that were synthetized by electrospinning and sequent thermaltreatment. The electrochemical performance of LCPFs/CPE was evaluated by cyclicvoltammetry and electrochemical impedance spectroscopy, and the resultsdemonstrated that it exhibits strong electrocatalytical activity towards the oxidationof L-tryptophan in0.1mol L-1phosphate buffer solution. The linear range ofL-tyrosine was0.05M–5M with a low detection limit (0.05M) and highsensitivity (123.43μA·μM–1·cm–2).4. A mild and novel preparation tactics based on electrochemical techniques forthe fabrication of electro-deposited graphene (E-GR) and polymerizedβ-cyclodextrin (P-βCD) nanocomposite film were developed. On the synergisticeffect of E-GR and P-βCD nanocomposite film, a super-sensitive electrochemicalsensor for quercetin was successfully manufactured. Under optimum conditions,linear response in the range of0.005–20μM was obtained with a low detectionlimit of1.0nM (S/N=3) for quercetin determination. To further study the practical applicability of the proposed sensor, determinations of real samples were carried outand satisfactory result was proved.5. A high sensitive catechol sensor and hydroquinone sensor were fabricatedbased on NiAl/LDHs ionic liquids doped ionic liquids (H-NiAl/LDHs). Theelectrochemical properties of the sensors were evaluated by cyclic voltammetry andelectrochemical impedance spectroscopy, and the results demonstrated thatH-NiAl/LDHs show excellent electrocatalytical activity towards the oxidation ofcatechol and hydroquinone. After optimizing the conditions, linear response in therange of0.01μM–140μM was obtained with a low detection limit of2.0nM(S/N=3) for hydroquinone determination. And the linear range of catechol was0.01μM-400μM with a2nM limit of detection (S/N=3).