CdSe:Eu nanocrystals were successfully synthesized and characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectric spectroscopy. The CdSe:Eu nanocrystals showed enhanced green electrochemiluminescence (ECL) intensity when compared to pure CdSe nanocrystals. Further, the nanocrystals were used to design an ECL immunosensor for the detection of carcinoembryonic antigen (CEA) that has a linear response over the 1.0 fg·mL?1 to 100 ng·mL?1 CEA concentration range with a 0.4 fg·mL?1 detection limit. The assay was applied to the determination of CEA in human serum samples.
Graphical abstract Schematic of the assay: GCE-glassy-carbon electrode, Ab- Antibody, BSA- Bovine serum albumin, Ag- Antigen. CdSe:Eu nanocrystals were used to design an ECL immunosensor for the detection of carcinoembryonic antigen.
The authors describe a sandwich-type electrochemical immunoassay for sensitive determination of the carcinoembryonic antigen (CEA). It is based on the use of iridium nanoparticles (Ir NPs) acting as electrochemical signal amplifier on the surface of a glassy carbon electrode. At first, polydopamine-reduced graphene oxide (PDA-rGO) was employed to immobilize primary antibody (Ab1) against CEA. Secondly, Ir-NPs were used as a support for the immobilization of secondary antibody (Ab2) to afford signal labels. The large surface area of PDA-rGO and the excellent electro-oxidative H2O2-sensing properties of Ir NPs result in a sensitive assay for CEA. Operated best at a working voltage of ?0.6 V (vs. SCE), the assay has a linear range that extends from 0.5 pg?mL?1 to 5 ng·mL?1, and the lower detection limit is 0.23 pg?mL?1. The immunosensor displays satisfactory reproducibility and stability, thus demonstrating a reliable immunoassay strategy for tumor biomarkers. It was applied to the determination of CEA in spiked serum samples.
Graphical abstract Schematic of an amperometric sandwich immunoassay for the carcinoembryonic antigen using a glassy carbon electrode modified with polydopamine, reduced graphene oxide and iridium nanoparticles
The authors describe a voltammetric immunoassay for the carcinoembryonic antigen (CEA). It is based on the use of a self-assembled magnetic nanocomposite as multifunctional signal amplification platform. The core of the nanocomposite consists of Fe3O4 microspheres, and the shell of zirconium hexacyanoferrate loaded with gold nanoparticles (AuNPs@ZrHCF@Fe3O4). The material was synthesized by an electrostatic self-assembly process which is caused by the strong interaction between cyano groups and AuNPs. The surface of the Fe3O4 microspheres was functionalized with amino groups to facilitate the immobilization of ZrHCF which acts as an electron mediator. The nanocomposite was placed on a glassy carbon electrode which then displays noteworthy electrocatalytic activity toward the reduction of hydrogen peroxide (H2O2). The AuNPs serve as a support for the immobilization of antibodies by the interaction between AuNPs and amino groups on antibodies to construct a covalent Au-N bond. This facilitates electron transfer on the electrode surface using H2O2 as the electrochemical probe. Square wave voltammetry (measured typically at +0.2 V vs. SCE) was carried out to record the electrochemical behavior. Under the optimal conditions, a response is linear in the 0.5 pg·mL?1 to 50 ng·mL?1 CEA concentration range, and the detection limit is as low as 0.15 pg·mL?1 (S/N =?3). The method is selective, highly stable and acceptably reproducible.
Graphical abstract A self-assembly magnetic nanocomposite for voltammetric immunoassay of CEA. GCE glassy carbon electrode; Au NPs gold nanoparticles; ZrHCF zirconium hexacyanoferrate; CEA carcinoembryonic antigen; Anti-CEA CEA antibody; BSA bovine serum albumin; SWV square wave voltammetry. A high sensitive voltammetric immunoassay method has been used for detecting CEA, It is based on a self-assembled magnetic nanocomposite (Au NPs@ZrHCF@Fe3O4) as multifunctional signal amplification platform.
We describe a label-free electrochemical immunosensor for the carcinoembryonic antigen (CEA). It is based on a nanocomposite consisting of electrochemically reduced graphene oxide, gold nanoparticles (AuNPs), and poly(indole-6-carboxylic acid). Coupled to nanoparticle-amplification techniques and modified with ionic liquid (IL), this immunoassay shows high sensitivity and good selectivity for CEA. At the best working voltage of 0.95 V (vs. Ag/AgCl), the lower detection limit is 0.02 ng·mL?1, and the response to CEA is linear in the range from 0.02 to 90 ng·mL?1. The method was applied to the determination of CEA in spiked serum samples and gave recoveries in the range from 98.5 % to 102 %.
Graphical abstract A label-free electrochemical immunosensor was fabricated for the carcinoembryonic antigen (CEA) with a detection limit of 0.02 ng·mL?1. It is based on a nanocomposite consisting of electrochemically reduced graphene oxide (erGO), gold nanoparticles (Au NP), and poly(indole-6-carboxylic acid) (PICA).
The authors describe a dye-sensitized photoelectrochemical immunoassay for the tumor marker carcinoembryonic antigen (CEA). The method employs the rhodamine dye Rh123 with red color and absorption maximum at 500 nm for spectral sensitization, and a 3D nanocomposite prepared from graphene oxide and MoS2 acting as the photoelectric conversion layer. The nanocomposite with flower-like 3D architectures was characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, and UV-vis diffuse reflectometry. A photoelectrochemical sandwich immunoassay was developed that is based on the use of the nanocomposite and based on the specific binding of antibody and antigen, and by using a secondary antibody labeled with Rh123 and CdS (Ab2-Rh123@CdS). Under optimal conditions and at a typical working voltage of 0 V (vs. Hg/HgCl2), the photocurrent increases linearly 10 pg mL?1 to 80 ng mL?1 CEA concentration range, with a 3.2 pg mL?1 detection limit.
Graphical abstract Flower-like GO-MoS2 complex with high efficiency of electron transport was synthesized to construct photoelectrochemical platform. The sandwich-type immunoassay was built on this platform based on specific binding of antigen and antibody. Carcinoembryonic antigen in sample was detected sensitively by using sensitization of rhodamine dye Rh123 as signal amplification strategy.
The authors describe an electrochemical immunoassay for the core antigen of hepatitis C virus (HCV). The method is based on the use of a screen-printed carbon electrode (SPCE) that was modified with a Nafion@TiO2 nanocomposite and loaded with secondary antibody (Ab2) to entrap Celestine Blue (CB). The material has architecture of the type CB/Ab2/Nafion@TiO2. A nanocomposite consisting of graphene, ionic liquid and fullerene was deposited on the SPCE first, and rhodium nanoparticles (RhNPs) were then deposited on the surface of modified electrode in order to immobilize primary antibody (Ab1). The antigen and CB/Ab2/Nafion@TiO2 were conjugated one by one to form a sandwich-type immunocomplex. The signal was obtained by differential pulse voltammetry whose intensity is related to the concentration of the antigen. The assay, if operated at a working voltage of typically 0.35 V (vs. Ag/AgCl) has a response that is linear in the 0.1 to 250 pg?mL?1 HCV core antigen concentration range, and the limit of detection is as low as 25 fg?mL?1. The assay was applied to the determination of the HCV core antigen in spiked human serum samples. In our perception, the method represents a promising platform for the detection of various antigens if appropriate antibodies are available.
Graphical abstract An electrochemical immunoassay for the core antigen of Hepatitis C virus was studied. A nanocomposite consisting of graphene, ionic liquid and fullerene was deposited on the SPCE and rhodium nanoparticles were deposited on the surface of modified electrode in order to immobilize primary antibody. Nafion@TiO2 was loaded with secondary antibody to entrap Celestine Blue.
The authors describe a voltammetric immunoassay for the carcinoembryonic antigen (CEA). A GCE was modified by electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with tannic acid (TA). Subsequently, four-armed poly(ethylene glycol) (PEG) was assembled onto the modified surface through hydrogen bonding. The fabrication steps were characterized by scanning electron microscopy, energy dispersive spectroscopy, fourier transform infrared spectroscopy, contact angle measurements, electrochemical impedance spectroscopy and differential pulse voltammetry. The PEG/TA-PEDOT surface is shown be super-hydrophilic and to possess anti-fouling capability. Antibody against CEA was then covalently immobilized on the electrode. By using hexacyanoferrate as an electrochemical probe and at a working potential of 0.18 V vs SCE, the amperometric response is linear in the 10 ag·mL?1 to 1.0 ng·mL?1 CEA concentration range, and the detection limit is as low as 4.8 ag·mL?1 (at an S/N ratio of 3). The assay was applied to the quantification of CEA in 1:10 diluted human serum samples. Recoveries ranged from 103.7 to 108.7%, and relative standard deviations from 2.9 to 4.8%.
Graphical abstract Schematic of an electrochemical immunosensor for the carcinoembryonic antigen (CEA). It is based on the use of tannic acid (TA) and poly(ethylene glycol) (PEG), both deposited on a glassy carbon electrode (GCE), and using hexacyanoferrate as the electrochemical probe. The sensor has a wide linear range and a 4.8 ag·mL?1 detection limit.
Tungsten disulfide (WS2) nanosheets were obtained by exfoliating WS2 bulk crystals in N-methylpyrrolidone by ultrasonication. Gold nanoparticles (GNPs) were synthesized by in-situ ultrasonication of sodium citrate and HAuCl4 while fabricating the WS2 nanosheets. In this way, the GNPs were self-assembled on WS2 nanosheets to form a GNPs/WS2 nanocomposite through interaction between sulfur and gold atoms. The photoelectrochemical response of WS2 nanosheets is significantly enhanced after integration of the GNPs. The GNPs/WS2 nanocomposite was coated onto a glassy carbon electrode (GCE) to construct a sensing interface which then was modified with an antibody against the carcinoembryonic antigen (CEA) to obtain a photoelectrochemical immunosensor for CEA. Under optimized conditions, the decline in relative photocurrent is linearly related to the logarithm of the CEA concentration in the range from 0.001 to 40 ng mL?1. The detection limit is 0.5 pg mL?1 (at S/N =?3). The assay is sensitive, selective, stable and reproducible. It was applied to the determination of CEA in clinical serum samples.
Graphical abstract Schematic presentation of the fabrication of Au/WS2 nanocomposites by in-situ ultrasonication and the procedure for the CEA photoelectrochemical immunosensor preparation, and the photocurrent response towards the carcinoembryonic antigen.
A binary nanocomposite of type copper tungstate and polyaniline (CuWO4@PANI) is described that was obtained by single step polymerization on the surface of a glassy carbon electrode (GCE). The resulting electrode is shown to be a viable tool for voltammetric sensing of quercetin (Qn) in blood, urine and certain food samples. The nanocomposite was characterized by UV-visible absorption spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and high-resolution transmission electron microscopy. Differential pulse voltammetry was applied to quantify Qn, typically at the relatively low working potential of 0.15 V (vs. Ag/AgCl). The modified GCE has a wide analytical range (0.001–0.500 μM) and a low detection limit (1.2 nM). The sensor is reproducible, selective and stable. This makes it suitable for determination of Qn in real samples without complicated sample pretreatment.
Graphical abstract Schematic of a copper tungstate and polyaniline nanocomposite modified glassy carbon electrode for voltammetric determination of quercetin in real samples.
A nanocomposite consisting of cadmium oxide decorated with carbon nanotubes (CdO.CNT NC) was prepared by a wet-chemical technique, and its optical, morphological, and structural properties were characterized by FTIR, UV/Vis, FESEM coupled to XEDS, XPS, and XRD methods. A flat glassy carbon electrode was modified with the nanocomposite to obtain a sensor for L-glutathione (GSH) which displays improved sensitivity, a large dynamic range and good long-term stability. The calibration plot (best acquired at a voltage of 0.5 V) is linear (r2 = 0.99) in the 0.1 nM to 0.01 M GSH concentration range. The detection limit is as low as 30.0 pM, and the sensitivity is ~9.49 μA?μM?1?cm?2. To the best of our knowledge, this is the first report on the determination of GSH using such a modified glassy carbon electrode (GCE) in combination with I-V method. The GCE was applied to the selective determination of GSH in spiked rabbit serum samples and gave acceptable results.
Graphical abstract A selective glutathione biosensor based on wet-chemically prepared CdO.CNT/Nafion/GCE was fabricated by reliable I-V method and shows good analytical parameters such as high sensitivity, low detection limit, long-term stability, and large dynamic range.
The family of zearalenones (ZENs) represents a major group of mycotoxins with estrogenic activity. They are produced by Fusarium fungi and cause adverse effects on human health and animal production. The authors describe here a label-free amperometric immunosensor for the direct determination of ZENs. A glassy carbon electrode (GCE) was first modified with polyethyleneimine-functionalized multi-walled carbon nanotubes. Next, gold and platinum nanoparticles (AuPt-NPs) were electro-deposited. This process strongly increased the surface area for capturing a large amount of antibodies and enhanced the electrochemical performance. In a final step, monoclonal antibody against zearalenone was orientedly immobilized on the electrode, this followed by surface blocking with BSA. The resulting biosensor was applied to the voltammetry determination of ZENs, best at a working voltage of 0.18 V (vs SCE). Under optimized conditions, the method displays a wide linear range that extends from 0.005 to 50 ng mL?1, with a limit of detection of 1.5 pg mL?1 (at an S/N ratio of 3). The assay is highly reproducible and selective, and therefore provides a sensitive and convenient tool for determination of such mycotoxins.
Graphical abstract An amperometric immunosensor for the direct determination of ZENs has been developed by immobilizing anti-ZEN monoclonal antibody on multi-walled carbon nanotubest hat were deposited, along with gold and platinum nanoparticles, on a glassy carbon electrode modified with Staphylococcus protein A.
The authors describe a method for signal amplification in electrochemical aptasensors. It is based on the induction of an increased electrochemical current by the aptamer captured on a glassy carbon electrode (GCE). The phosphate groups on the aptamer backbone are brought to reaction with added molybdate to form a redox-active molybdophosphate precipitate on the surface of the GCE that generates a strong electrochemical current. To further enhance sensitivity, gold nanorods (GNRs) were selected as a support for the immobilization of aptamers. The aptasensor was applied to the determination of the cancer biomarker carcinoembryonic antigen (CEA) in a sandwich format. Antibody against CEA, CEA (antigen) and GNRs modified with CEA aptamer were sequentially captured on the GCE. The resulting aptasensor, best operated at a voltage as low as 0.18 V vs. Ag/AgCl, is highly sensitive and has a wide linear range that extends from 0.1 pg·mL?1 to 10 ng·mL?1 of CEA. This amplification strategy uses an aptamer as both the recognition probe and signal probe and therefore simplifies signal transduction. Conceivably, this detection scheme may be adapted to numerous other electrochemical bioassays if respective antibodies and aptamers are available.
Graphical abstract Schematic presentation of an electrochemical aptasensor based on aptamer induced electrochemical current for the detection of cancer biomarker carcinoembryonic antigen (CEA). Gold nanorods (GNR) are chosen for the immobilization of aptamers to increase the loading of aptamers.
The authors describe a method for signal amplification of label-free voltammetric immunosensors. A glassy carbon electrode (GCE) was modified with Prussian Blue-platinum nanoparticles (PB-PtNPs) as a redox-active species that gives a strong amperometric signal at 0.18 V (vs. Ag/AgCl). Benefitting from the excellent electrical conductivity and the strong catalytic activity to H2O2, the modified GCE gives a strongly enhanced signal. The PB-PtNPs were incorporated into a polyaniline (PANI) hydrogel to further enhance the signal. The signal response of the PB-PtNP-PANI/GCE is larger by a factor of 7.6 than that of PB-PtNP/GCE. In order to further improve electrical conductivity and immobilize antibody, gold nanoparticles (AuNPs) were deposited on the surface of the PB-PtNP-PANI hydrogel. The AuNP-PB-PtNP-PANI hydrogel nanocomposite on the GCE was used in an immunosensor for the model analyte carcinoma antigen 125 (CA125), a biomarker for epithelial ovarian cancer, by immobilizing the respective antibody on the modified GCE. A linear response found for the 0.01 to 5000 U mL?1 CA125 concentration range, with a detection limit of 4.4 mU mL?1 (at an S/N ratio of 3). The electrochemical sensitivity is as high as 119.76 μA·(U/mL)?1·cm?2. The detection of CA125 in human serum showed satisfactory accuracy compared to a commercial chemiluminescent microparticle immunoassay (CMIA).
Graphical abstract Schematic of a nanocomposites consisting of gold nanoparticles, Prussian Blue, platinum nanoparticles and polyaniline hydrogel as a signal multi-amplification sensing substrate for the ultrasensitive immuno detection of carcinoma antigen 125 (CA125).
A dual enhancing strategy has been employed to develop a sandwich type of electrochemical immunoassay for the prostate specific antigen (PSA). The signal is enhanced by using Pt-Cu hierarchical trigonal bipyramid nanoframes (HTBNFs) and a composite consisting of Fe3O4 nanoparticles and reduced graphene oxide in polydopamine that serve to capture the primary antibody (Ab1). This nanocomposite shows better electrical conductivity than Fe3O4 and reduced graphene oxide (RGO), respectively, alone. The Pt-Cu HTBNFs were used to label the secondary antibody (Ab2) and act as tags for signal amplification by virtue of their outstanding electrochemical reduction activity towards H2O2. At a working potential of +0.1 V (vs. SCE), the interference by dissolved oxygen can be avoided. This immunoassay is highly sensitive, with a linear range that extends from 0.1 pg?mL?1 to 5 ng?mL?1 and an ultralow detection limit of 0.03 pg?mL?1.
Graphical abstract Schematic of the dual amplification strategy in the immunosensor for the prostate specific antigen (PSA) that is based on the use of a first antibody (Ab1) conjugated to a Fe3O4-reduced graphene oxide nanocomposite (Fe3O4-RGO), and of Pt-Cu trigonal bipyramid nanoframes as a label for the second antibody (Ab2).
We describe a high-performance nitric oxide (NO) sensor by using a nanocomposite consisting of platinum-tungsten alloy nanoparticles, sheets of reduced graphene oxide and an ionic liquid (PtW/rGO-IL) that was deposited onto the surface of a glassy carbon (GC) electrode. The modified GC electrode exhibits excellent electrocatalytic activity toward the oxidation of NO with a strong peak at 0.78 V vs. Ag/AgCl due to the synergistic effects of bimetallic PtW nanoparticles, reduced graphene oxide nanosheets and an ionic liquid. The sensor possesses a detection limit as low as 0.13 nM, high sensitivity (3.01 μA μM?1 cm2), and good selectivity over electroactive interferents that may exist in biological systems. The sensor was tested to selectively distinguish NO in actual human serum and urine samples, confirming potential practical applications. In our perception, the approach described here may be extended to the fabrication of various kind of composites made from metal nanostructures, graphene and ionic liquids for medical and environmental analysis.
Graphical abstract Enhanced electrochemical sensing of nitric oxide (NO) is demonstrated by utilizing the synergistic effects of bimetallic PtW nanoparticles dispersed on reduced graphene oxide and ionic liquid nanocomposite.
A nanocomposite was prepared from graphene-like two-dimensional black phosphorene (BP, an allotrope of phosphorus) and nafion (Nf) treated with isopropanol (IP). A glassy carbon electrode (GCE) modified with this nanocomposite was found to be a viable sensor for voltammetric determination of clenbuterol (CLB). Unlike previously reported pure BP, the BP nanocomposite was stable towards water and oxygen. Its morphology, structure, electrochemically active surface area and electrochemical stability were investigated. The BP-Nf (IP) modified GCE displayed good electrochemical stability and electrocatalytic capacity with a low working potential of 0.94 V (vs. SCE), excellent peak current response for CLB in a linear concentration range of 0.06–24 μM with a detection limit of 3.7 nM (3σ/m) and a sensitivity of 0.14 μA·μM?1·cm?2 under optimal conditions. A sensing mechanism for the electro-oxidation of CLB was suggested and verified by density functional theory calculations under imitation of aqueous solution conditions. The sensor was successfully applied to the determination of CLB in bovine meat and bovine serum samples.
Graphical abstract Highly-stable black phosphorene (BP) nanocomposite based on Nafion (Nf) was used to modify a glassy carbon electrode (GCE). It is shonw to be a viable electrochemical platform for sensitive voltammetric determination of trace clenbuterol (CLB) in bovine beef and bovine serum.
The authors report an aptaelectrode based on graphene modified iron-oxide chitosan hybrid (CHIT-IO-GR) nanocomposite film deposited on fluorine tin oxide (FTO) for the detection of the Mycobacterium tuberculosis specific antigen MPT64. The biotinylated DNA aptamer sequence specific to the MPT64 was immobilized onto the CHIT-IO-GR/FTO electrode by using streptavidin-biotin interactions. XRD, FT-IR, FE-SEM and electrochemical studies were applied to monitor the steps of the fabrication. The aptaelectrode, operated best at typical voltage of 0.44 V, exhibited a limit of detection (LOD) of 0.9 fg?mL?1 within 20 min. The biosensor retained about 80% of its initial activity after 10 uses. The potential application of the aptasensor was established by spike-in studies to obtain recoveries between 83 and 95%.
Graphical abstract An electrochemical aptaelectrode based on nanocomposite consisting of chitosan (CHIT), iron-oxide nanoparticles (IO) and functionalized graphene (GR) has been fabricated to detect M. tb antigen MPT64 with an LOD of 0.9 fg?mL?1 within 20 min.
A conductive hydrogel acting as a redox-active species was synthesized by crosslinking phytic acid as a ligand and lead(II) as the metal ion. The resulting gelatine-like material displays excellent redox activity and facilitates the transport of electrons and ions. Gold nanoparticles were electrochemically deposited on the hydrogel film, and antibody against cytokeratin antigen was immobilized thereon. An amperometric immunosensor for cytokeratin antigen 21–1 (CYFRA21-1), a kind of biomarker of lung cancer, was obtained by deposition of the composite on a glassy carbon electrode. If operated at ? 0.58 V (vs. Ag/AgCl), the sensor exhibits a linear detection range that extends from 50 fg mL?1 to 100 ng mL?1 CYFRA21-1, and a 38 fg mL?1 detection limit (at a signal to noise ratio of 3). The quantitation of CYFRA21-1 in (spiked) human serum samples showed satisfactory accuracy compared to an ELISA.
Graphical abstract A conductive hydrogel acting as a redox-active species was synthesized by crosslinking phytic acid as a ligand and lead(II) as the metal ion, which was used to fabricate an ultrasensitive label-free amperometric immunosensor for tumor marker.
A glassy carbon electrode (GCE) modified with polymeric nanocomposite consisting of palladium nanoparticles and a conductive polymeric ionic liquid was prepared. The modified GCE was applied to sensitive and fairly selective electrochemical determination of the mycotoxin zearalenone. Electrocatalytic oxidation is performed in a solution containing 20 % (V/V) acetonitrile and 80 % (V/V) of 1 M perchloric acid. Cyclic voltammetry and square wave voltammetry revealed a well-defined electrocatalytic peak current at overpotential of +0.69 V versus Ag/AgCl. Under optimized experimental conditions, there is a linear relationship between anodic peak current and zearalenone concentration in the range from 0.03 to 35 ng?mL￣1, and the detection limit is 0.01 ng?mL￣1. The method was successfully applied to the analysis of zearalenone in spiked food samples and gave recoveries between 95.6 and 104.0 %.
Graphical abstract The nanocomposite (PdVC-PIL) was prepared by polymerization of ionic liquid monomer (PIL) in presence of Pd nanoparticles on Vulcan XC-72R carbon (PdVC). The solution containing nanocomposite was placed on the glassy carbon electrode (GCE). The voltammetry activity of modified electrode (PdVC-PIL/GCE) was compared to a bare GCE for zearalenone determination.
A highly selective and sensitive aptasensor is described for voltammetric determination of the pesticide chlorpyrifos (CPS). The sensor was constructed by modifying a glassy carbon electrode (GCE) with gold nanorods and a polymer that was molecularly imprinted with an aptamer against CPS. This results in double specific recognition. Under optimal conditions and a working potential as low as 0.22 V (vs. Ag/AgCl), the nanotools has a dynamic range that covers the 1.0 fM - 0.4 pM CPS concentration range, and the detection limit is 0.35 fM. This is lower than any of the previously reported methods. This MIP-aptasensor is selective over structural analogs, stable, and adequately reproducible. It was successfully applied to the determination of CPS in spiked food samples.
Graphical abstract Impedimetric detection of Chlorpyrifos by using a Fe(CN)63?/4- probe based on double recognition of aptamer-molecular imprinted polymer onto a glassy carbon electrode modified with gold nanorod nanocomposite. The incubation with Chlorpyrifos lead to an increase of electron transfer resistance.
