Gold Working Electrode Research Articles

An improved method for direct estimation of free cyanide in drinking water by Ion Chromatography-Pulsed Amperometry Detection (IC-PAD) on gold working electrode

In the present work a fast, reliable and safe Ion Exchange Chromatography-Pulsed Amperometry Detection (IC-PAD) method for direct determination of free cyanide in drinking water has been reported. To the best of our knowledge for the first time we are reporting the application of Gold working electrode for detection of free cyanide in a chromatography system. The system shows a wide linear range up to 8000µg/L. The electrode was found to have improved sensitivity and selectivity in the presence of interfering ions. The detection limit of the system was calculated to be 2µg/L. Long term evaluation of the electrode was found to be stable. Reproducible results were obtained from analysis of drinking water samples with recoveries of 98.3–101.2% and Relative Standard Deviations (RSD) of <2%. This study proves the potential application of the newly developed method for the analysis of free cyanide in drinking water.

Ruthenium Complexes with Strongly Electron-Donating Terpyridine Ligands: Effect of the Working Electrode on Electrochemical and Spectroelectrochemical Properties.

The combination of 2,2':6',2''-terpyridines (tpy) and RuII is known to deliver molecular and supramolecular assemblies with remarkable properties. Here new RuII complexes, with modified tpy ligands substituted with varying numbers of dimethlyamino groups, are presented. Electrochemistry shows that the incorporation of the strongly electron-donating groups on the tpy ligands leads to a negative shift of the RuII oxidation potential by close to 1 V. The reductive electrochemical responses are strongly dependent on the nature of the working electrode, with glassy carbon and gold working electrodes showing the best results. These observations led to the development of a modified Optically Transparent Thin Layer Electrochemical (OTTLE) cell, based on a gold working electrode. The use of UV/Vis/NIR spectroelectrochemical methods with that OTTLE cell, together with simulations of the cyclic voltammograms, allowed the characterization of four reduction steps in these complexes, the final two of which lead to bond activations at the ruthenium center. This observation is to the best of our knowledge unprecedented in coordinatively saturated complexes of type [Ru(tpy)2 ]2+ . The various redox states of the complexes were characterized by EPR spectroelectrochemistry and through DFT calculations. The results presented here establish these substituted tpy ligands as highly attractive ligands in coordination chemistry, and display the utility of a gold-based OTTLE cell for spectroelectrochemical measurements.

A Novel Graphene Modified Electrochemical Sensor for Ultrasensitive Detection of T1D Serum Autoantibody

Recently, autoantibody biomarkers have been reported for early diagnosis of type 1 diabetes (T1D) also known as insulin-dependent diabetes mellitus or juvenile diabetes. Our objective is to design an electrochemical immunosensor to detect glutamic acid decarboxylase antibodies (GADA) from serum as a diagnostic measure for T1D. The sensor is designed on a screen printed eight electrode array (AuSPE) made of gold working electrodes, gold counter electrode, and a silver pseudo reference electrode. Protein A/G coated magnetic beads were used to capture the GADA spiked in 5% human serum samples. The antibody-captured by the magnetic beads were allowed to bind with the surface antigen (GAD-65) immobilized onto the carboxylated graphene oxide modified working electrode surface by carbodiimide chemistry. Both differential pulse voltammetry and Faradaic electrochemical impedance techniques were able to detect ultra-low levels of GADA. Acknowledgements: We are grateful for the financial support by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award Number R15DK103386.

Hydrophobic Water Probed Experimentally at the Gold Electrode/Aqueous Interface.

Quantitative description of reaction mechanisms in aqueous phase electrochemistry requires experimental characterization of local water structure at the electrode/aqueous interface and its evolution with changing potential. Gaining such insight experimentally under electrochemical conditions is a formidable task. The potential-dependent structure of a subpopulation of interfacial water with one OH group pointing towards a gold working electrode is characterized using interface specific vibrational spectroscopy in a thin film electrochemical cell. Such free-OH groups are the molecular level observable of an extended hydrophobic interface. This free-OH interacts only weakly with the Au surface at all potentials, has an orientational distribution that narrows approaching the potential of zero charge, and disappears on oxidation of the gold electrode.

Hydrophobic Water Probed Experimentally at the Gold Electrode/Aqueous Interface

AbstractQuantitative description of reaction mechanisms in aqueous phase electrochemistry requires experimental characterization of local water structure at the electrode/aqueous interface and its evolution with changing potential. Gaining such insight experimentally under electrochemical conditions is a formidable task. The potential‐dependent structure of a subpopulation of interfacial water with one OH group pointing towards a gold working electrode is characterized using interface specific vibrational spectroscopy in a thin film electrochemical cell. Such free‐OH groups are the molecular level observable of an extended hydrophobic interface. This free‐OH interacts only weakly with the Au surface at all potentials, has an orientational distribution that narrows approaching the potential of zero charge, and disappears on oxidation of the gold electrode.

A Single-Use, In Vitro Biosensor for the Detection of T-Tau Protein, A Biomarker of Neuro-Degenerative Disorders, in PBS and Human Serum Using Differential Pulse Voltammetry (DPV).

A single-use, in vitro biosensor for the detection of T-Tau protein in phosphate-buffer saline (PBS) and undiluted human serum was designed, manufactured, and tested. Differential pulse voltammetry (DPV) served as the transduction mechanism. This biosensor consisted of three electrodes: working, counter, and reference electrodes fabricated on a PET sheet. Both working and counter electrodes were thin gold film, 10 nm in thickness. Laser ablation technique was used to define the size and structure of the biosensor. The biosensor was produced using cost-effective roll-to-roll process. Self-assembled monolayers (SAM) of 3-mercaptopropionic acid (MPA) were employed to covalently immobilize the anti-T-Tau (T-Tau antibody) on the gold working electrode. A carbodiimide conjugation approach using N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide hydrochloride (EDC) and N–hydroxysuccinimide (NHS) cross-linked anti-T-Tau to the carboxylic groups on one end of the MPA. A T-Tau protein ladder with six isoforms was used in this study. The anti-T-Tau concentration used was 500,000 pg/mL. The T-Tau protein concentration ranged from 1000 pg/mL to 100,000 pg/mL. DPV measurements showed excellent responses, with a good calibration curve. Thus, a practical tool for simple detection of T-Tau protein, a biomarker of neuro-degenerative disorders, has been successfully developed. This tool could also be extended to detect other biomarkers for neuro-degenerative disorders, such as P-Tau protein and β-amyloid 42.

Mediated Catalytic Voltammetry of Holo and Heme‐Free Human Sulfite Oxidases

AbstractHerein, we report the electrocatalytic voltammetry of holo and heme‐free human sulfite oxidase (HSO) mediated by the synthetic iron complexes 1,2‐bis(1,4,7‐triaza‐1‐cyclononyl)ethane iron(III) bromide, ([Fe(dtne)]Br3.3H2O), potassium ferricyanide (K3[Fe(CN)6]), and ferrocene methanol (FM) at a 5‐(4′‐pyridinyl)‐1,3,4‐oxadiazole‐2‐thiol (Hpyt) modified gold working electrode. Holo HSO contains two electroactive redox cofactors, comprising a mostly negatively charged cyt b5 (heme) domain and a Mo cofactor (Moco) domain (the site of sulfite oxidation), where the surface near the active site is positively charged. We anticipated different catalytic voltammetry based on either repulsive or attractive electrostatic interactions between the holo or heme‐free enzymes and the positively or negatively charged redox mediators. Both holo and heme‐free HSO experimental catalytic voltammetry has been modeled by using electrochemical simulation across a range of sweep rates and concentrations of substrate and both positive and negatively charged electron acceptors ([Fe(dtne)]3+, [Fe(CN)6]3− and FM+), which provides new insights into the kinetics of the HSO catalytic mechanism. These mediator complexes have almost the same redox potential (all lying in the range +415 to +430 mV vs. NHE) and, thus, deliver the same driving force for electron transfer with the Mo cofactor. However, differences in the electrostatic affinities between HSO and the mediator have a significant influence on the electrocatalytic response.

Determination of IPTG in Recombinant Human Growth Hormone with Ion Chromatography and Pulsed Electrochemical Detection

A novel method for the determination of isopropyl-β-D-thiogalactopyranoside (IPTG), a sulfur-containing compound, a pharmaceutical additive in commercial recombinant human growth hormone (rhGH), has been developed using pulsed electrochemical detection (PED), following ion Chromatographic separation. A Dionex-500 ion chromatograph coupled with an electrochemical detector was employed, equipped with a gold working electrode and an Acclaim 300 analytical C18 column, with a mobile phase consisting of sodium acetate (NaOAc) buffer (pH 5.45, 0.01 mol/L) and acetonitrile (ACN)(90/10, v/v). Upon optimization, IPTG was found to have a limit of detection of 1 ng/mL (0.1 μmol) with 25 uL injection volume. This method was successfully applied to the determination of IPTG in rhGH samples with the characteristics of simplicity, high sensitivity and good repeatability.

Determination of isopropyl- β -D-thiogalactopyranoside in recombinant human growth hormone using reversed-phase high performance liquid chromatography and pulsed electrochemical detection

A novel method for the determination of isopropyl- β -D-thiogalactopyranoside (IPTG), a sulfur-containing compound, a pharmaceutical additive in commercial recombinant human growth hormone (rhGH), has been developed using pulsed electrochemical detection (PED), following liquid chromatographic separation. A Dionex-500 ion chromatograph coupled with an electrochemical detector was employed, equipped with a gold working electrode and an Acclaim 300 analytical C18 column, with a mobile phase consisting of sodium acetate (NaOAc) buffer (pH 5.45, 0.01 mol/L) and acetonitrile (ACN) (90:10, v/v). The C18 phase has very high surface coverage, resulting in high capacity. Electrochemical characterization via cyclic voltammetry is the basis of optimization of the integrated pulsed amperometric detection (IPAD) waveform. PED at a gold electrode has proven to be selective for sulfur-containing compounds under mildly acidic conditions. Upon optimization, IPTG was found to have a limit of detection of 1 μg/L (0.1 pmol) with 25 uL injection volume. This method was successfully applied to the determination of IPTG in rhGH samples with the characteristics of simplicity, high sensitivity and good repeatability. The assay is also useful, efficient and low-cost in monitoring disulfide formation kinetics and assuring quality control for biopharmaceuticals.

Membrane-based electrochemical device for monitoring nanowires in aqueous samples

We report a membrane-based electrochemical detection of nanowires in aqueous sample. A gold-coated membrane is used both as a membrane filter and a working electrode. Using filtration method, it is possible to concentrate silver and zinc oxide nanowires on the gold working electrode on top of the membrane and the nanowires on the electrode can be differentiated and quantified by differential pulse voltammetry. Moreover, the new method shows better reproducibility in comparison with conventional immersion method, without modification of electrode surface according to the nanomaterial to be detected.

Faster Diagnosis of Alpha-1-Antitrypsin Deficiency through Electrochemical and Quartz Crystal Microbalance Testing

Alpha-1-Antitrypsin (A1AT) Deficiency (A1AD) is a potentially debilitating inherited condition that can lead to reduced levels of A1AT in the lungs and increased levels in the liver. In the lungs, the condition is routinely associated with an imbalance in levels of Human Neutrophil Elastase (HNE) and its native inhibitor A1AT (predisposing those affected to early-onset emphysema). In the liver, certain genetic mutations lead to an accumulation of A1AT. No cure exists, and current approaches for diagnosis are insufficient as illustrated by the fact that A1AD is underdiagnosed and diagnosis is often delayed.1New methods for diagnosis are needed, and one possible route is the use of electrochemical techniques combined with quartz crystal microbalance (QCM) approaches. Often, QCM and electrochemistry are combined using a gold working electrode that has been functionalized with a particular molecule. In our case, Porcine Pancreatic elastase (PPE), a surrogate of HNE, has been used as an enzymatic marker. When a potentiostat was combined in parallel to the apparatus, measurements of both the frequency and the current responses were simultaneously performed. PPE was immobilized to the surface of the gold electrode through the use of a crosslinker. The immobilized PPE was then incubated with various concentrations of N-Succinyl-Ala-Ala-Ala-p-Nitroanalide (SApNA), a chromogenic substrate for elastase, allowed to react, and the absorbance measured to determine the activity of the enzyme. This same test was also completed with the A1AT inhibitor in the solution with the SApNA and the absorbance measured again. From these results, the frequency was measured and converted to mass to determine the extent of inhibition. This data was then examined via kinetics-based models to estimate the kinetic parameters of inhibition. Electrochemical measurements have been performed concurrently with the frequency measurements. Using phosphate buffered saline (PBS) in the presence of ferrocyanide/ferricyanide as the redox species, cyclic voltammetry was performed to determine the extent that the electrode surface is covered. As the SApNA and A1AT was added to the solution, the change in the ferrocyanide/ferricyanide peaks were observed. It is the ultimate goal of this work to develop a test that can be used to determine the inhibition kinetics of HNE via A1AT, and thus shed light on new approaches to diagnose A1AD. Such an approach could also serve as a platform that could be useful in the early detection and diagnosis of many different diseases that could allow for preemptive treatment and could potentially improve life expectancy outcomes for those afflicted. American Thoracic Society/European Respiratory Society Statement: Standards for the Diagnosis and Management of Individuals with Alpha-1-Antitrypsin Deficiency. (2003). Am. J. Respir. Crit. Care Med. 168(7): 818-900.

Novel strategy for sulfapyridine detection using a fully integrated electrochemical Bio-MEMS: Application to honey analysis

Sulfapyridine (SPy) is a sulfonamide antibiotic largely employed as veterinary drugs for prophylactic and therapeutic purposes. Therefore, its spread in the food products has to be restricted. Herein, we report the synthesis and characterization of a novel electrochemical biosensor based on gold microelectrodes modified with a new structure of magnetic nanoparticles (MNPs) coated with poly(pyrrole-co-pyrrole-2-carboxylic acid) (Py/Py-COOH) for high efficient detection of SPy. This analyte was quantified through a competitive detection procedure with 5-[4-(amino)phenylsulfonamide]-5-oxopentanoic acid-BSA (SA2-BSA) antigens toward polyclonal antibody (Ab-155). Initially, gold working electrodes (WEs) of integrated biomicro electro-mechanical system (BioMEMS) were functionalized by Ppy-COOH/MNPs, using a chronoamperometric (CA) electrodeposition. Afterward, SA2-BSA was covalently bonded to Py/Py-COOH/MNP modified gold WEs through amide bonding. The competitive detection of the analyte was made by a mixture of a fixed concentration of Ab-155 and decreasing concentrations of SPy from 50µgL−1 to 2ngL−1. Atomic Force Microscopy characterization was performed in order to ensure Ppy-COOH/MNPs electrodeposition on the microelectrode surfaces. Electrochemical measurements of SPy detection were carried out using electrochemical impedance spectroscopy (EIS). This biosensor was found to be highly sensitive and specific for SPy, with a limit of detection of 0.4ngL−1. This technique was exploited to detect SPy in honey samples by using the standard addition method. The measurements were highly reproducible for detection and interferences namely, sulfadiazine (SDz), sulfathiazole (STz) and sulfamerazine (SMz). Taking these advantages of sensitivity, specificity, and low cost, our system provides a new horizon for development of advanced immunoassays in industrial food control.

Mixed Zwitterion-Based Self-Assembled Monolayer Interface for Impedimetric Glycomic Analyses of Human IgG Samples in an Array Format.

An impedimetric lectin biosensor for the detection of changes in the glycan structure of antibodies isolated from human serum is here correlated with the progression of rheumatoid arthritis (RA). The biosensor was built up from a mixed self-assembled monolayer (SAM) on gold consisting of two different thiolated zwitterionic derivatives, carboxybetaine and sulfobetaine, to resist nonspecific interactions. The carboxyl-terminated one was applied also for the covalent immobilization of lectin Ricinus communis agglutinin I (RCA-I). The process of building a bioreceptive layer was optimized and characterized using a diverse range of techniques. Impedimetric assays were integrated on a chip consisting of eight gold working electrodes, which is an important step toward the achievement of a moderate level of multiplexing for the analysis of human serum samples. At the end, the results obtained by the impedimetric analysis of immunoglobulins G (IgGs) isolated from serum samples were compared with those of two other standard bioanalytical methods employing lectins, that is, lectin microarrays (MAs) and enzyme-linked lectin binding assays (ELLBAs). The impedimetric results agreed very well with the DAS28 index (RA disease activity score 28), suggesting that impedimetric assays could be used for the development of a new diagnostic procedure sensitive to glycosylation changes in human IgGs and thus RA progression.

Carbon tape coated with gold film as stickers for bulk fabrication of disposable gold electrodes to detect Cr(VI)

Fabrication of disposable gold working electrodes in bulk is desirable for their extensive application in electrochemical detection. In this paper the gold film electrodes were prepared by sputtering the gold film with the thickness of ∼12nm on the double sided conductive carbon tape. The gold film coated carbon tape could be used like stickers with small square pieces and attached on ITO glass for fabrication of disposable gold film electrodes. The electrochemical responses of the gold film modified electrodes on Cr(VI) in acidic solutions were similar to previous gold electrodes, suggesting the similar mechanism as before. Cr(VI) could be determined by the amperometric method with the detection limit of 0.7μgL−1 (0.013μM), which was significantly improved compared with previously reported disposable gold-based electrodes. The batch-by-batch (n=20) reproducibility of the fabricated electrodes was 7.3% at 50μgL−1 and 3.8% at 5.0mgL−1, respectively. The disposable electrodes could be applied to quantify Cr(VI) in real samples including plastics, tap water and lake water with results in agreement with those obtained with HPLC-ICP-MS. This study provides a simple and effective alternative for preparation of disposable gold film electrodes.

Development of a new microbial biosensor based on conductive polymer/multiwalled carbon nanotube and its application to paracetamol determination

In this study, a new microbial biosensor based on Bacillus subtilis was developed for sensitive determination of paracetamol. The microbial biosensor was modified by using carboxylated multiwalled carbon nanotube (cMWCNT) and conductive polymer, polyaniline (PANI) in presence of glutaraldehyde on a gold working electrode. Paracetamol measurements by the microbial biosensor were carried out at 0.5V applied potential with amperometric method. In the optimization studies of the microbial biosensor, the effect of (amount or concentration of) the bioactive layer components such as MWCNT, PANI, Bacillus sp. were carried out. In addition, working conditions of the microbial biosensor such as pH and temperature were also investigated.In the characterization studies of the biosensor some paramaters such as linearity, reproducibility, storage stability, substrat specificity and interference effect on the biosensor responses were determined. In the reproducibility experiments (n=7), the average value, standard deviation, (SD) and coefficent of variation (CV%) were calculated to be 250.65μM, ±1.55, 0.62% for 250μM paracetamol concentration, consecutively. Detection limit was calculated as 2.9μM by using visual evaluation mehod. In addition, paracetamol was carried out in drug samples by the developed biosensor.

Critical View on Electrochemical Impedance Spectroscopy Using the Ferri/Ferrocyanide Redox Couple at Gold Electrodes.

Electrochemical or faradaic impedance spectroscopy (EIS) using the ferri/ferrocyanide couple as a redox probe at gold working electrodes was evaluated with respect to its ability to monitor consecutive surface modification steps. As a model reaction, the reversible hybridization and dehybridization of DNA was studied. Thiol-modified single stranded DNA (ssDNA, 20 bases, capture probe) was chemisorbed to a gold electrode and treated with a solution of short thiols to release nonspecifically adsorbed DNA before hybridization with complementary ssDNA (20 bases, target) was carried out. Reversible dehybridization was achieved by intense rinsing with pure water. The experimental procedures were optimized by kinetic surface plasmon resonance (SPR) and quartz crystal microbalance with dissipation (QCM-D) measurements to maximize the increase in reflectivity or decrease in frequency upon hybridization before hybridization/dehybridization was also monitored by EIS. In contrast to SPR and QCM-D, repeatable EIS measurements were not possible at first. Combined SPR/EIS and QCM-D/EIS measurements revealed that during EIS the gold surface is seriously damaged due to the presence of CN(-) ions, which are released from the ferri/ferrocyanide redox probe. Even at optimized experimental conditions, etching the gold electrodes could not be completely suppressed and the repeatability of the EIS measurements was limited. In three out of four experimental runs, only two hybridization/dehybridization steps could be monitored reversibly by EIS. Thereafter etching the gold electrode significantly contributed to the EIS spectra whereas the QCM-D response was still repeatable. Hence great care has to be taken when this technique is used to monitor surface modification at gold electrodes.

NO2-Selective Electrochemical Sensors for Diesel Exhausts

Electrochemical NOx sensors based on yttria-stabilized zirconia (YSZ) are commercialized to detect overall NOx concentrations in Diesel exhausts without distinction between NO and NO2. To overcome this inconvenient, a high-sensitive sensor based on selective electrochemical reduction of NO2 is proposed. An electrochemical cell consisting of three metallic electrodes on solid-state electrolyte (YSZ) operating under electric polarization between a gold working electrode and a platinum counter electrode allows selective NO2 detection at 400-550°C with high sensitivity, and without any significant interferences to other gases like hydrocarbons, carbon monoxide and also ammonia and nitrogen monoxide. A mechanism based on cathodic overpotential is proposed.

Thermoresponsive amperometric glucose biosensor.

The authors report on the fabrication of a thermoresponsive biosensor for the amperometric detection of glucose. Screen printed electrodes with heatable gold working electrodes were modified by a thermoresponsive statistical copolymer [polymer I: poly(ω-ethoxytriethylenglycol methacrylate-co-3-(N,N-dimethyl-N-2-methacryloyloxyethyl ammonio) propanesulfonate-co-ω-butoxydiethylenglycol methacrylate-co-2-(4-benzoyl-phenoxy)ethyl methacrylate)] with a lower critical solution temperature of around 28 °C in aqueous solution via electrochemically induced codeposition with a pH-responsive redox-polymer [polymer II: poly(glycidyl methacrylate-co-allyl methacrylate-co-poly(ethylene glycol)methacrylate-co-butyl acrylate-co-2-(dimethylamino)ethyl methacrylate)-[Os(bpy)2(4-(((2-(2-(2-aminoethoxy)ethoxy)ethyl)amino)methyl)-N,N-dimethylpicolinamide)](2+)] and pyrroloquinoline quinone-soluble glucose dehydrogenase acting as biological recognition element. Polymer II bears covalently bound Os-complexes that act as redox mediators for shuttling electrons between the enzyme and the electrode surface. Polymer I acts as a temperature triggered immobilization matrix. Probing the catalytic current as a function of the working electrode temperature shows that the activity of the biosensor is dramatically reduced above the phase transition temperature of polymer I. Thus, the local modulation of the temperature at the interphase between the electrode and the bioactive layer allows switching the biosensor from an on- to an off-state without heating of the surrounding analyte solution.

Rotating Ring-Disk Electrode and Quantum-Chemical Study of the Electrochemical Reduction of Monoiodoacetic Acid and Iodoform.

This study examined the electrochemical (EC) reduction of monoiodoacetic acid (MIAA) and iodoform (CHI3), which are typical iodine-containing disinfection byproducts (I-DBPs). Experiments carried out using the method of a rotating ring-disk electrode (RRDE) with a gold working electrode showed that the reduction of CHI3 and MIAA is diffusion-controlled. The MIAA diffusion coefficient was determined to be (1.86 ± 0.24)·10(-5) cm(2) s(-1). The yield of the iodide ion formed as a result of MIAA or CHI3 reduction was affected by the presence of dissolved organic matter (DOM) and resorcinol. Increasing concentrations of DOM or resorcinol did not affect the EC reduction of the examined I-DBPs, but the formation of iodide was suppressed. This indicated that free iodine, ·I, was formed as a result of the first step in the EC reduction of MIAA and CHI3. This also indicated that the pathway of the EC reduction of MIAA and CHI3 was different from that typical for the reduction of Br- and Cl-containing DBPs, in which case Br(-) or Cl(-) tend to be formed as a result of the electron transfer. Quantum-chemical (QC) calculations confirmed the thermodynamic likelihood of and possible preference to the formation of free iodine species as a result of the EC reduction of MIAA, CHI3, and other I-DBPs.

Voltammetric determination of antioxidant 4,4′-methylenebis(2,6-di-tert-butylphenol) in lubricating oils using gold disc electrode

A novel method for voltammetric determination of 4,4′-methylenebis(2,6-di-tert-butylphenol) antioxidant was developed employing linear sweep voltammetry and gold working electrode. Different supporting electrolytes were applied during development of this methodology and 0.05 mol dm−3 H2SO4 containing ethanol with 6.6 % toluene was selected as the suitable medium to ensure a sufficient solubility of the analyte. In this work, the electrochemical behavior of the mentioned antioxidant was investigated and different voltammetric techniques were compared. The developed method based on linear sweep voltammetry was purposed for determination of the antioxidant in base oil. It was found that this matrix does not allow the direct voltammetric determination of the antioxidant, thus, the sample pretreatment, namely the extraction with ethanol, was necessary. The proposed electroanalytical method enabled the determination of antioxidants in model and real samples with satisfactory results and provides good prospects for practical analysis.