Nonenzymatic Amperometric Sensor Research Articles

A non-enzymatic hydrogen peroxide sensor based on poly(vinyl alcohol)–multiwalled carbon nanotubes–platinum nanoparticles hybrids modified glassy carbon electrode

The present work describes an effective strategy to fabricate a highly sensitive and fast response sensor for non-enzymatic hydrogen peroxide (H 2 O 2 ) determination. Platinum nanoparticles (PtNPs) were electrodeposited onto the multiwalled carbon nanotubes (MWCNTs) which were non-covalently functionalized by freezing–thawing poly(vinyl alcohol) (PVA). The PVA-solubilized MWCNTs could form uniform film on a glassy carbon (GC) electrode, which was considered as a promising support for electrodeposition of metal particles. The PVA–MWCNTs–PtNPs hybrids showed an excellent electrocatalytic activity and offered a significant decrease in the overvoltage for H 2 O 2 reduction, as a result of synergic action of PtNPs and MWCNTs. The PVA–MWCNTs–PtNPs hybrids modified sensor exhibited a wide linear range of 0.002–3.8 mM, a remarkable sensitivity of 122.63 μA mM −1 cm −2 at a low potential of 0 mV, a lower detection limit of 0.7 μM at the signal-to-noise ratio of 3, and a fast response time (within 5 s). Additionally, it showed an excellent reproducibility, long-term stability and anti-interference performance. The current work could provide a feasible approach and potential platform to fabricate a variety of non-enzymatic amperometric sensors.

Direct electrochemical non-enzymatic assay of glucose using functionalized graphene

A non-enzymatic amperometric sensor is developed based on the graphite electrode modified with functionalized graphene for the determination of β, d (+)-glucose. Cyclic voltammetry and electrochemical impedance spectroscopy techniques are used to study the behavior. Atomic force microscopy was used to study the surface topography of the working electrode before and after its modification. The sensor enabled the direct electrochemical oxidation of β, d (+)-glucose in alkaline medium and responded linearly to the analyte over the range from 0.5 × 10−3 to 7.5 × 10−3 M with a limit of detection of 10 μM. The sensor is found to exhibit a better sensitivity of 28.4 μA mM−1 cm−2, good stability, and shelf life. The sensitivity of the sensor to β, d (+)-glucose was not affected by the commonly co-existing interfering substances such as l-ascorbic acid, dopamine, uric acid, and acetaminophen.

A non-enzymatic amperometric sensor for glucose based on cobalt oxide nanoparticles

A cobalt oxide nanoparticle-modified glassy carbon (CONM/GC) electrode was prepared by potential cycling in a pH-controlled solution containing tartrate. The electrocatalytic oxidation of glucose on CONM/GC electrode in alkaline solution was investigated and the kinetics was developed. In cyclic voltammograms, the peak current of the oxidation of low valence cobalt oxide in the presence of glucose is increased and it was followed by a decrease in the corresponding cathodic current. This suggested that glucose oxidation was being catalysed on the redox mediator with an electrocatalytic mechanism. Using cyclic voltammetry, chronoamperometry, steady-state polarisation measurements and impedance spectroscopy, the kinetic parameters of the glucose electrooxidation such as charge-transfer coefficient, the catalytic reaction rate constant and the diffusion coefficient were determined. Based on the results, an efficient enzyme-less sensing procedure for determination of glucose was developed. The resulting sensor exhibited excellent performance for the glucose determination and a sensitive and time-saving amperometric procedure was successfully applied for the quantification of glucose in both batch and flow systems. Glucose was determined with a linear range of 0.7–60 µM, a limit of detection of 0.15 µM and a sensitivity of 2515.35 µA mM−1 cm−2 in batch system and with a linear range of 1.3–50 µM, a limit of detection of 0.14 µM and a sensitivity of 3240.25 µA mM−1 cm−2 in the flow system.

Non-enzymatic amperometric sensor for hydrogen peroxide based on a biocomposite made from chitosan, hemoglobin, and silver nanoparticles

We report on a novel non-enzymatic sensor for hydrogen peroxide (HP) that is based on a biocomposite made up from chitosan (CS), hemoglobin (Hb), and silver nanoparticles (AgNPs). The AgNPs were prepared in the presence of CS and glucose in an ultrasonic bath, and CS is found to act as a stabilizing agent. They were then combined with Hb and CS to construct a carbon paste biosensor. The resulting electrode gave a well-defined redox couple for Hb, with a formal potential of about −0.17 V (vs. SCE) at pH 6.86 and exhibited a remarkable electrocatalytic activity for the reduction of HP. The sensor was used to detect HP by flow injection analysis, and a linear response is obtained in the 0.08 to 250 μM concentration range. The detection limit is 0.05 μM (at S/N = 3). These characteristics, along with its long-term stability make the sensor highly promising for the amperometric determination of HP.

Nonenzymatic amperometric organic peroxide sensor based on nano-cobalt phthalocyanine loaded functionalized graphene film

An enzyme-free amperometric method was established for the electrochemical reduction tert-butyl hydroperoxide (TBHP) on the utilization of nano-cobalt phthalocyanine (CoPc) loaded functionalized graphene (FGR) and to create a highly responsive organic peroxide sensor. FGR was synthesized with a simple and fast method of electrolysis with potassium hexafluorophosphate (KPF 6) solution as electrolyte under the static current of 0.2 A. In the present work, FGR was dispersed in the solution of CoPc to fabricate chemical modified electrode to detect TBHP. The electro-reduction of TBHP can be catalyzed by FGR–CoPc, which has an excellent electrocatalytical activity due to the synergistic effect of the FGR with CoPc. The sensor can be applied to the quantification of TBHP with a linear range covering from 0.0260 to 4.81 mM, a high sensitivity of 13.64 A M −1, and a low detection limit of 5 μM. This proposed sensor was designed as a simple, robust, and cheap analytical device for the determination of TBHP in body lotion.

Non-enzymatic hydrogen peroxide amperometric sensor based on a glassy carbon electrode modified with an MWCNT/polyaniline composite film and platinum nanoparticles

We report on a non-enzymatic amperometric sensor for hydrogen peroxide (H2O2). It was fabricated by electrodeposition of multi-wall carbon nanotubes and polyaniline along with platinum nanoparticles on the surface of a glassy carbon electrode. The modification was probed by scanning electron microscopy and cyclic voltammetry. The resulting sensor exhibits a high sensitivity (748.4 μA·mM−1·cm−2), a wide linear range (7.0 μM–2.5 mM), a low detection limit (2.0 μM) (S/N = 3), a short response time (>5 s), and long-term stability, and is not interfered by common species. It was successfully applied to determine H2O2 in disinfectants.

The nanocomposite of PtPd nanoparticles/onion-like mesoporous carbon vesicle for nonenzymatic amperometric sensing of glucose

A facile and fast microwave irradiation method was developed to prepare PtPd bimetallic alloy nanoparticles on onion-like mesoporous carbon vesicle (MCV). With MCV acts as a template, its high surface area favors the formation of nanosized PtPd particles. The PtPd/MCV nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron micrographs (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). A nonenzymatic amperometric sensor of glucose based on the PtPd/MCV modified glassy carbon (GC) electrode is developed. Compared with the Pt/MCV nanocomposite, the PtPd/MCV modified electrode displays enhanced current response towards glucose and gives linear range from 1.5 to 12 mM. The particular lamellar structure of the MCV results in favorable transport passage for glucose. The modified electrode achieves 95% of the steady-current within 3 s. This nonenzymatic glucose sensor also exhibits good ability of anti-interference to electroactive molecules. The fast response and facile preparation method make PtPd/MCV nanocomposite promising for the development of enzyme-free sensor for glucose.

Protein-Promoted Synthesis of Pt Nanoparticles on Carbon Nanotubes for Electrocatalytic Nanohybrids with Enhanced Glucose Sensing

A facile and effective strategy to create carbon nanotube (CNT)-based platinum nanoparticle (PtNP) nanohybrids is reported in this work. First, we prepared toluene-soluble CNTs by modifying CNTs with a bifunctional linker, Z-glycine N-succinimidyl ester (Z-Gly-OSu), and then we synthesized super-water-soluble CNT–hemoglobin (HGB) hybrid nanofibers (about 5 mg/mL) by phase-transferring the Z-Gly-OSu-modified CNTs from toluene to HGB aqueous solution. The prepared CNT–HGB nanofibers were used as templates to bind PtCl62– ions by electrostatic interaction between proteins and negatively charged ions. CNT–PtNP nanohybrids were successfully synthesized by chemically reducing the PtCl62– ions with NaBH4. The results indicate that PtNPs with uniform size and shape were created on the side wall of CNTs with high dispersion, and the loading of PtNPs on CNTs was improved with the increase of protein concentration used for the preparation of CNT–HGB nanofibers. A nonenzymatic amperometric sensor for highly sensitive and selective detection of glucose was successfully fabricated as demonstrating based on the synthesized CNT–PtNP nanohybrids. Under optimal conditions, selective detection of glucose in a linear concentration range of 28.0 μM–46.6 mM (R = 0.996) was obtained, which reveals a lower limit of detection and wider linear response compared to some previously reported glucose sensors.

Porous Cu–NiO modified glass carbon electrode enhanced nonenzymatic glucose electrochemical sensors

Porous Cu-NiO nanocomposites were successfully prepared by calcination of the Cu-Ni(OH)(2) precursor at 400 °C for 2 h. During the process of calcination, Ar was used to deaerate O(2). The structure and morphology of Cu-NiO were characterized by X-ray diffraction spectrum (XRD), energy dispersive X-ray analyses (EDX), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Using porous Cu-NiO nanocomposites, a simple non-enzymatic amperometric sensor has been fabricated (Cu-NiO/GCE) and evaluated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and typical amperometric method. When applied to detect glucose by the amperometric method, Cu-NiO/GCE produced an ultrahigh sensitivity of 171.8 μA mM(-1), with a low detection limit of 0.5 μM (S/N = 3). What's more, interference from common co-existing species, such as UA, AA, and fructose can be avoided at the sensor. Results in this study imply that porous Cu-NiO nanocomposites are promising nanomaterials for the enzyme-free determination of glucose.

A nonenzymatic sensor for xanthine based on electrospun carbon nanofibers modified electrode

Xanthine (Xa) determination is of considerable importance in clinical analysis and food quality control. Therefore, a sensitive nonenzymatic amperometric sensor for Xa based on carbon nanofibers (CNFs) has been proposed. The CNFs, which were prepared by electrospinning technique and subsequent thermal treatment, were used to modify carbon paste electrode (CNF-CPE) to construct the amperometric sensor device without any oxidation pretreatment. In application to Xa electrochemical determination, the CNF-CPE exhibited high electrocatalytic activity and fast amperometric response. Various experimental parameters, such as pH and applied potential were optimized. Under the optimal conditions, the dynamic linear range of Xa was 0.03–21.19μM (R=0.9992) with the detection limit low to 20nM (S/N=3). With good selectivity and sensitivity, the present system was successfully applied to estimate the freshness of fish and determine Xa in human urine, which provides potential application in food quality control and clinical analysis.

A simple hydrothermal synthesis of nickel hydroxide–ordered mesoporous carbons nanocomposites and its electrocatalytic application

A simple hydrothermal synthesis of nickel hydroxide–ordered mesoporous carbons nanocomposites (Ni(OH) 2–OMCs) is proposed for the first time. The characterization of the new material shows that, after anchoring Ni(OH) 2 nanoparticles on the mesoporous, ordered mesostructure of the nanocomposites remain intact and Ni(OH) 2 is electrochemically accessible. The performance of Ni(OH) 2–OMCs is compared to OMCs and the properties of the new material are found to be improved. A sensor for sensitive detection of underivatized glycine has been developed based on Ni(OH) 2–OMCs modified glass carbon (Ni(OH) 2–OMCs/GC) electrode. The linear response of glycine measurement was up to about 3.2 mM with a high sensitivity of 10.5 μA mM −1 for the Ni(OH) 2–OMCs/GC electrode. The detection limits was estimated to be 0.26 μM (S/N = 3). Then ethanol was selected as another marked molecule, a nonenzymatic amperometric sensor of ethanol based on the Ni(OH) 2–OMCs nanocomposites is also constructed. The linear response of ethanol measurement was up to about 80 mM with a sensitivity of 0.65 μA mM −1. The detection limits was estimated to be 4.77 μM (S/N = 3).

Nonenzymatic Electrochemical Glucose Sensor Based on Pt Nanoparticles/Mesoporous Carbon Matrix

AbstractA nonenzymatic amperometric sensor for sensitive and selective detection of glucose has been constructed by using highly dispersed Pt nanoparticles supported onto mesoporous carbons (MCs). The Pt nanoparticles/mesoporous carbons (Pt/MCs) composites modified electrode displayed high electrocatalytic activity towards the oxidation of glucose. At an applied potential of 0.1 V, the Pt/MCs electrode has a linear dependence (R=0.996) in the glucose concentration up to 7.5 mM with a sensitivity of 8.52 mA M−1 cm−2. The Pt/MCs electrode has also shown highly resistant toward poisoning by chloride ions and without interference from the oxidation of common interfering species.

Addition of porous cuprous oxide to a Nafion film strongly improves the performance of a nonenzymatic glucose sensor

The direct electrocatalytic oxidation of glucose in alkaline medium at an electrode modified with microcubes of porous cuprous oxide is reported. Compared to the glassy carbon electrode, a substantial increase in the efficiency of the electrocatalytic oxidation of glucose is observed starting at around +0.20 V (vs. Ag/AgCl). The pH dependence of the response was examined by cyclic voltammetry. This non-enzymatic amperometric sensor may be used for non-enzymatic detection of glucose with a high and reproducible sensitivity of 10.95 μA per mM at a potential of +0.40 V, with response times of <3 s, a linear range from 2.0 to 350 μM, and a detection limit of 1.3 μM. The porous microcubes are conveniently prepared, and display high sensitivity and repeatability.

A sensitive amperometric sensor for hydrazine and hydrogen peroxide based on palladium nanoparticles/onion-like mesoporous carbon vesicle

Onion-like mesoporous carbon vesicle (MCV) with multilayer lamellar structure was synthesized by a simply aqueous emulsion co-assembly approach. Palladium (Pd) nanoparticles were deposited on the MCV matrix (Pd/MCV) by chemical reduction of H 2PdCl 4 with NaBH 4 in aqueous media. Pd( X)/MCV ( X wt.% indicates the Pd loading amount) nanocomposites with different Pd loading amount were obtained by adjusting the ratio of precursors. The particular structure of the MCV results in efficient mass transport and the onion-like layers of MCV allows for the obtainment of highly dispersed Pd nanoparticles. The introduction of Pd nanoparticles on the MCV matrix facilitates hydrazine oxidation at more negative potential and delivers higher oxidation current in comparison with MCV. A linear range from 2.0 × 10 −8 to 7.1 × 10 −5 M and a low detection limit of 14.9 nM for hydrazine are obtained at Pd(25)/MCV nanocomposite modified glassy carbon (GC) electrode. A nonenzymatic amperometric sensor for hydrogen peroxide based on the Pd(25)/MCV nanocomposite modified GC electrode is also developed. Compared with MCV modified GC electrode, the Pd(25)/MCV nanocomposite modified GC electrode displays enhanced amperometric responses towards hydrogen peroxide and gives a linear range from 1.0 × 10 −7 to 6.1 × 10 −3 M. The Pd(25)/MCV nanocomposite modified GC electrode achieves 95% of the steady-current for hydrogen peroxide within 1 s. The combination of the unique properties of Pd nanoparticles and the porous mesostructure of MCV matrix guarantees the improved analytical performance for hydrazine and hydrogen peroxide.

Nonenzymatic amperometric sensor of hydrogen peroxide and glucose based on Pt nanoparticles/ordered mesoporous carbon nanocomposite

A simple and facile synthetic method to incorporate Pt nanoparticles inside the mesopores of ordered mesoporous carbons (OMCs) is reported. The Pt/OMCs nanocomposite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and nitrogen adsorption–desorption. The results show that the incorporation of Pt nanoparticles inside the pores of OMCs does not change the highly ordered two-dimensional hexagonal mesostructure of OMCs matrix. Nonenzymatic amperometric sensor of hydrogen peroxide and glucose based on the Pt/OMCs nanocomposite-modified glassy carbon (GC) electrode is developed. Compared with the original OMCs-modified electrode, the Pt/OMCs-modified electrode displays improved current response towards hydrogen peroxide and gives linear range from 2 to 4212 μM. At an applied potential of −0.08 V, the Pt/OMCs nanocomposite gives linearity in the range of 0.5–4.5 mM glucose in neutral buffered saline solution. This glucose sensor also exhibits good ability of anti-interference to electroactive molecules. The combination the unique properties of Pt nanoparticles and the ordered mesostructure of OMCs matrix guarantees the enhanced response for hydrogen peroxide and glucose.

In situ growth of copper sulfide nanoparticles on ordered mesoporous carbon and their application as nonenzymatic amperometric sensor of hydrogen peroxide

A simple and facile synthetic method to incorporate copper sulfide (Cu(2)S) nanoparticles inside the mesopores of ordered mesoporous carbons (OMCs) is reported. The Cu(2)S/OMCs nanocomposite was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption. The results show that the incorporation of Cu(2)S nanoparticles inside the pores of OMCs does not change the highly ordered two-dimensional hexagonal mesostructure of OMCs matrix. Nonenzymatic amperometric sensor of hydrogen peroxide based on the Cu(2)S/OMCs nanocomposite modified glassy carbon (GC) electrode is developed. Compared with the pristine OMCs modified electrode, the Cu(2)S/OMCs modified electrode displays high electrocatalytic activity towards hydrogen peroxide and gives linear range from 1 to 3030 microM (R=0.9986). The sensor also exhibits good ability of anti-interference to electroactive molecules. The combination of the unique properties of Cu(2)S nanoparticles and the ordered mesostructure of OMCs matrix guarantee the excellent electrocatalysis for hydrogen peroxide. The good analytical performance and low-cost make Cu(2)S/OMC nanocomposite promising for the development of effective sensor for hydrogen peroxide.

Porous cuprous oxide microcubes for non-enzymatic amperometric hydrogen peroxide and glucose sensing

Using porous cuprous oxide (Cu 2O) microcubes, a simple non-enzymatic amperometric sensor for the detection of H 2O 2 and glucose has been fabricated. Cyclic voltammetry (CV) revealed that porous Cu 2O microcubes exhibited a direct electrocatalytic activity for the reduction of H 2O 2 in phosphate buffer solution and the oxidation of glucose in an alkaline medium. The non-enzymatic amperometric sensor used in the detection of H 2O 2 with detection limit of 1.5 × 10 −6 M over wide linear detection ranges up to 1.5 mM and with a high sensitivity of 50.6 μA/mM. This non-enzymatic voltammetric sensor was further utilized in detection of glucose with a detection limit of 8.0 × 10 −7 M, a linear detection range up to 500 μM and with a sensitivity of −70.8 μA/mM.