Graphene Paste Electrode Research Articles

Electrochemical sensor based on reduced graphene oxide paste electrode for detection of gemcitabine as a chemotherapy drug in breast cancer

The development of a precise and sensitive electrochemical sensor is essential in the field of medical diagnostics in order to identify gemcitabine, a chemotherapy drug that is commonly used to treat breast cancer. This work presents a novel electrochemical sensor based on a reduced graphene oxide (rGO) nanocomposite and a zirconium-based metal-organic framework (Zr-MOF) with terephthalic acid as a ligand. Gemcitabine (GEM), a chemotherapy medication used to treat breast cancer, is detected with remarkable sensitivity and selectivity by the Zr-MOF-rGO modified graphene paste electrode (GrPE) sensor. By combining the strong structure and active sites of Zr-MOF with the large surface area and electrical conductivity of rGO, the sensor's design maximizes electron transfer rates and GEM adsorption capacity. The sensor outperforms current GEM sensors with its wide linear detection range (0.5–490 μM) and low detection limit (0.008 μM). The sensor's long-term analytical applicability is confirmed by stability and reusability studies, which produced accuracy rates surpassing 94 % and RSD values below 4.21 % in recovery trials using spiked human blood serum and urine samples. Overall, the results of this investigation show that the Zr-MOF-rGO/GrPE electrode has the potential to be a useful platform for the detection of gemcitabine in patients with breast cancer.

Electrochemically Polymerized DL‐Phenylalanine‐Deposited Graphene Paste Electrode for the Detection of Rutin

AbstractThe sensitive, economical, green, and simple voltammetric sensor for the detection of the redox behaviour of rutin (RT) was prepared by the electrochemical polymerization approach. The constructed polymerized DL‐phenylalanine (DL‐PN) modified graphene paste electrode (MGPE) and bare graphene paste electrode (BGPE) were elucidated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopic (EIS) and field emission scanning electron microscopic (FE‐SEM) approaches. The analysis of RT in phosphate‐buffered saline (PBS) of pH 6.5 was demonstrated by the application of a modified electrode (Poly(DL‐PN)MGPE) with higher electrocatalytic activity and active sites as compared to BGPE. The important electrochemical parameters such as the influence of PBS, pH, scan rate, and concentration of RT on Poly(DL‐PN)MGPE were evaluated. The variation of scan rate and PBS pH assessment discloses that the RT redox nature at Poly(DL‐PN)MGPE surface has proceeded via pH‐dependant and adsorption‐controlled pathways. The Poly(DL‐PN)MGPE senses RT in the range from 0.2 to 10.0 μM with a lower limit of detection (LOD) value of 8.31 nM and a limit of quantification (LOQ) of 27.70 nM. The Poly(DL‐PN)MGPE shows excellent reproducibility, antifouling nature, repeatability, and stability for the detection of RT. Also, the Poly(DL‐PN)MGPE analytical applicability was discussed for RT detection in citrus fruit juice samples.

Electrochemical Analysis of Food additive Vanillin using Poly (Aspartic Acid) Modified Graphene and Graphite composite Paste Sensor

AbstractVanillin (VLN) is generally used in bakery food products as an aroma enhancer and flavoring agent. Hence it is important to develop a powerful and rapid tool to monitor the concentration of VLN levels concerning food safety. In this paper, a simple sensor was proposed by electropolymerized Aspartic acid (ASP) modified on Graphene and Graphite composite paste electrode (PASPMGN/CPE) for the detection of VLN by differential pulse voltammetry (DPV). PASPMGN/CPE ranked to have high electrocatalytic kinetics towards electro‐oxidation of VLN, in optimized conditions. The electrochemical process of VLN is portrayed to be irreversible and adsorption‐controlled kinetics by the cyclic voltammetry (CV) method. The surface features were studied using Field Emission Scanning Electron Microscopy (FE‐SEM), Energy Dispersive X‐ray Spectroscopy (EDX), Electrochemical Impedance Spectroscopy (EIS) and CV. From DPV results, the oxidative peak current showed linear growth toward the concentration of VLN ranging from 1.0 μM to 15.0 μM with a limit of detection and quantification of 4.85 μM and 16.2 μM. The modified sensor attained to be highly selective with common possible interferents. PASPMGN/CPE was efficient in detecting VLN in vanilla pods, essence and bakery product samples.

Electrochemical Polymerisation of Glutamic Acid on the Surface of Graphene Paste Electrode for the Detection and Quantification of Rutin in Food and Medicinal Samples.

Rutin (RU) is one of the best-known natural antioxidants with various physiological functions in the human body and other plant species. In this work, an efficient voltammetric sensor to detect RU in food samples was explicated using a poly (glutamic acid)-modified graphene paste electrode (PGAMGPE). In order to detect RU, the proposed sensor diminishes material resistance and overpotential while increasing kinetic rate, peak currents, and material conductance. Using differential pulse voltammetry (DPV) and cyclic voltammetry (CV), the analysing efficiency of a PGAMGPE and a Bare graphene paste electrode (BGPE) was evaluated in 0.2 M phosphate buffer (PB) at an ideal pH of 6.5. in a potential window of -0.25 V to 0.6 V. Electrochemical impedance spectroscopy (EIS) was used to analyse the prepared electrode materials' conductivity, charge transfer resistance, and the kinetics of electron transport. Field emission scanning electron microscopy (FE-SEM) images were considered to compare the exterior morphology of the PGAMGPE and the BGPE. It was discovered that the PGAMGPE and the BGPE have electroactive surfaces of 0.062 cm2 and 0.04 cm2, respectively. It was determined that two protons and two electrons participated in the redox process. The resultant limit of detection (LOD) was found to be 0.04 µM and 0.06 µM, respectively, using DPV and CV methods. In spite of common interferents such as metal ions and chemical species, the developed sensor's selectivity for RU detection was impressive. For the simultaneous analysis of RU in the presence of caffeine (CF), the PGAMGPE affords a good electrochemical nature for RU with good selectivity. Due to the good stability, repeatability, reproducibility, and ease of use of the present RU sensor, it is useful for real sample analysis such as food and medicinal samples with recovery ranging from 94 to 100%.

Analytical Performance of Clay Paste Electrode and Graphene Paste Electrode-Comparative Study.

The analytical performance of the clay paste electrode and graphene paste electrode was compared using square wave voltammetry (SWV) and cyclic voltammetry (CV). The comparison was made on the basis of a paracetamol (PA) determination on both working electrodes. The influence of pH and SWV parameters was investigated. The linear concentration ranges were found to be 6.0 × 10−7–3.0 × 10−5 and 2.0 × 10−6–8.0 × 10−5 mol L−1 for clay paste electrode (ClPE) and graphene paste electrode (GrPE), respectively. The detection and quantification limits were calculated as 1.4 × 10−7 and 4.7 ×10−7 mol L−1 for ClPE and 3.7 × 10−7 and 1.2 × 10−6 mol L−1 for GrPE, respectively. Developed methods were successfully applied to pharmaceutical formulations analyses. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to characterize ClPE and GrPE surfaces. Clay composition was examined with wavelength dispersive X-ray (WDXRF).

Sensitive and selective electrochemical detection of vanillin at graphene based poly (methyl orange) modified electrode

Vanillin (VN) is a flavouring substance commonly used in the food and pharmaceutical industry. The rampant use of VN has significant implications on human health. In this work, a sensitive and selective voltammetric sensor to detect VN in food essences and natural vanilla beans was elucidated using a poly(methyl orange) modified graphene paste electrode (PMOMGPE). The surface morphology of PMOMGPE and a bare graphene paste electrode (BGPE) was compared using field emission - scanning electron microscopy (FE-SEM) and electron transfer kinetics were analysed by Electrochemical impedance spectroscopy (EIS). The electrochemical activities of PMOMGPE and BGPE were assessed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in 0.2 M phosphate buffer solution (PBS) of an optimum pH of 6.5 with an accumulation time of 20 s in a potential window of 0.2 V–1 V. Superior electrocatalytic activity was observed by PMOMGPE for the oxidation of VN, which is attributed to the high surface area and interactions between the polymer film and analyte. The VN sensor exhibited a low detection limit of 7.35 × 10−8 M by the DPV method and 20.19 × 10−8 M by the CV method. Various parameters like heterogeneous rate constant (ko = 1.7 × 10−5 cm s−1), number of electrons transferred (n = 2), and surface concentration (Γ = 0.8 nmol cm−2) were calculated. The selectivity of the prepared sensor for VN detection in the presence of common interferents such as metal ions and organic species was noteworthy. PMOMGPE was reliably used for the simultaneous analysis of VN along with indigo carmine (IC) and tartrazine (TZ). This facile VN sensor can be effectively used for real sample analysis, due to its simplicity and stability.

Electroanalytical Determination of Tinidazole by using Surface Modified Carbon Nano Composite based Sensor

ABSTRACT As an antibiotic, tinidazole (TNZ) is usually consumed to reduce the bacterial infection; thus, qualitative determination of the TNZ is very significant. Thus, in this article, the development of voltammetric sensor based on poly-threonine-modified carbon nanotube-mixed graphene paste electrode (PTRMCNTMGPE) for the detection of TNZ was reported. The PTRMCNTMGPE displayed a boosted electrocatalytic effect regarding the voltammetric signal of the TNZ (pH 7.0) compared to the bare electrode. The morphology of the proposed electrodes was characterised by field emission scanning electron microscopy. The charge transfer resistance of the designed electrode was studied through electrochemical impedance spectroscopy. The impact of pH and effect of scan rate was studied. The scan rate study reveals the reduction process of the TNZ was controlled by diffusion. The designed electrode yielded low detection limit (0.2 µM) for TNZ. The proposed electrode exhibited a good reproducibility, repeatability, selectivity and an antifouling feature. The practicability of the developed sensor was explored by detecting the TNZ in tablet and blood serum samples.

Fabrication of Efficient and Selective Modified Graphene Paste Sensor for the Determination of Catechol and Hydroquinone

An electrochemical sensor, based on a graphene paste electrode (GPE), was modified with a polymerization method, and the electrochemical behavior of catechol (CC) and hydroquinone (HQ) was investigated using electroanalytical methods like cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The effect of CC at the modified electrode was evidenced by the positive shift of the oxidation peak potential of CC at the poly (rosaniline)-modified graphene paste electrode (PRAMGPE) and the nine-fold enhancement of the peak current, as compared to a bare graphene paste electrode (BGPE). The sensitivity of CC investigated by DPV was more sensitive than CV for the analysis of CC. The DPV method showed the two linear ranges of 2.0 × 10−6–1.0 × 10−5 M and 1.5 × 10−5–5 × 10−5 M. The detection limit and limit of quantification were determined to be 8.2 × 10−7 and 27.6 × 10−7 M, respectively. The obtained results were compared successfully with respect to those obtained using the official method. Moreover, this sensor is applied for the selective determination of CC in the presence of HQ. The high sensitivity, good reproducibility, and wide linear range make the modified electrode suitable for the determination of CC in real samples. The practical application of the sensor was demonstrated by determining the concentration of CC in water samples with acceptable recoveries (97.5–98%).

Electroanalytical Performance of Graphene Paste Electrode Modified Al(III)-TiO2 Nanocomposites in Fipronil Solution

The new composite material Al(III)-TiO2 has been synthesized and applied as a modifier of graphene paste electrode for the determination of fipronil pesticide by cyclic voltammetry. The methods were to synthesis of Aluminum-Titanium dioxide (AT), preparation of graphene paste electrode with mass varied Al(III)-TiO2 (GAT) (0.05 g, 0.1 g, 0.2 g), and fipronil electroanalytic respons. Addition of Al(III)-TiO2 to the graphene paste electrode shows redox properties which are well characterized by a fast electron transfer process. Based on the results of measurements in a solution containing fipronil, it is known that fipronil is oxidized at a potential value of 0.26 V. Furthermore, the fipronil oxidation process on the GAT surface is influenced by diffusion control, this is powered by R2 value 0.91 when plotted between peak oxidation currents (Ip­a) vs. root scan rate. Other results show that measurement linearity is in the range 0.01 to 0.09 µg/L with a limit of detection (LOD) value of 0.0164 μg/L. Moreover, GAT shows good stability in the determination of fipronil with% RSD equal to 5%.

Poly (Adenine) Modified Graphene-Based Voltammetric Sensor for the Electrochemical Determination of Catechol, Hydroquinone and Resorcinol

Objective: This paper presents the application of Poly (Adenine) Modified Graphene Paste Electrode (PAMGPE) for the analysis of Catechol (CC) with Resorcinol (RC) and Hydroquinone (HQ) by a voltammetric technique. Methods: Electropolymerization technique was utilized for the modification of the sensor surface. The electrode surface was characterized by Field Emission Scanning Electron Microscopy (FE-SEM). Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) were used to study the redox behavior of CC, RC and HQ. Results: Oxidation peak current of CC increased linearly with the concentration of CC in the range from 2×10-6- 8×10-6 M and 1×10-5-1.5 ×10-4 M with a detection limit of 2.4×10-7 M. The practical application of the developed sensor was verified as exact for the determination of CC in water sample. Conclusion: The stability, repeatability, and reproducibility of the developed electrode were studied and established good characteristics. Furthermore, the PAMGPE was examined for the simultaneous determination of CC, RC and HQ.

Comparative Electroanalytical Studies of Graphite Flake and Multilayer Graphene Paste Electrodes.

In this paper, the fabrication, surface characterisation and electrochemical properties of graphite flake (GFPE) and multilayer graphene (MLGPE) paste electrodes are described. The Raman investigations and scanning electron microscopy were used to analyze and compare structure of both carbon materials. The electroanalytical performance of both electrodes was examined and compared on the basis of the square-wave and cyclic voltammetric behavior of acetaminophen and model redox systems. Results of those studies revealed that GFPE has a larger electroactive surface area and better conductive properties, whilst MLGPE demonstrate better analytical characteristic in case of acetaminophen (AC) determination. AC determination was developed using square wave voltammetry (SWV) and square wave stripping voltammetry (SWSV). For both working electrodes, the process of accumulation enabled us to obtain an extended linear range and to lower the detection limit. In pharmaceutical formulations, AC was determined with good recovery.

Microfabricated paper-based vanadium co-laminar flow fuel cell

Paper-based vanadium membraneless co-laminar flow fuel cells with graphene paste electrodes are developed to enhance the power density. The developed fuel cells are precisely microfabricated utilizing photolithography and screen printing methods for flow channel patterning and electrode forming, respectively. The measured fuel cell performances change with varying concentrations of fuel/oxidant (0.5–2.0 M V2+/VO2+) and a support electrolyte (0.5–4.0 M H2SO4). The maximum power density (15.09 ± 1.05 mW cm−2) and maximum current density (30 ± 0.62 mA cm−2) are the highest for concentrations of 2.0 M vanadium redox couple and 2.0 M sulfuric acid. The performance of the proposed fuel cell is also affected by contact with air. Regardless of air contact, the prototype paper-based vanadium fuel cell shows higher performance than those of previously reported paper-based co-laminar flow fuel cells. This novel proof-of-concept fuel cell is important for achieving the required power density for practical use of paper-based microfluidic fuel cells.

Fabrication of novel polymer-modified graphene-based electrochemical sensor for the determination of mercury and lead ions in water and biological samples

BackgroundThis paper presents the application of polyglycine-modified graphene paste electrode (PGMGPE) for the electrochemical detection of Hg (II) and Pb (II) ions in the water and biological samples.MethodThe developed electrode was characterized by field emission scanning electron microscopy. Electrochemical techniques such as cyclic voltammetry and differential pulse voltammetry were used to study the behavior of metal ions.ResultsThe modification process improves the electrochemical behavior of heavy metal ions. The peak current varied linearly with the increase of the concentration leading to a detection limit of 6.6 μM (Hg (II)) and 0.8 μM (Pb (II)), respectively.ConclusionThe developed electrode exhibits good sensitivity, selectivity, stability, and lower detection limit, and was successfully applied to the determination of heavy metal ions in water and biological samples with a good recovery range.

The influence of lateral flake size in graphene/graphite paste electrodes: an electroanalytical investigation

We report the electroanalytical properties of graphene and graphite paste electrodes comprising varying lateral flake sizes when applied for sensing relevant biomolecules and prominent drugs of abuse.

A simple approach for the electrochemical determination of vanillin at ionic surfactant modified graphene paste electrode

This paper describes a simple approach for the determination of vanillin (VN) based on the ionic surfactant modified graphene paste electrode. The electrochemical behavior of VN at the modified electrode is investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), suggests the modified electrode exhibits excellent electrochemical activity towards VN compared to the bare electrode. VN shows an irreversible behavior, and the nature of the electrode response was noticed to be adsorption controlled. Under the optimized conditions, the anodic peak current for VN was proportional to VN concentration from 4 × 10−6 to 1.5 × 10−5 M and 2 × 10−5 to 7 × 10−5 M with a limit of detection 1.29 µM. The developed method was effectively applied in the determination of VN in commercial food samples with good recovery.

A surfactant enhanced graphene paste electrode as an effective electrochemical sensor for the sensitive and simultaneous determination of catechol and resorcinol

Abstract A highly sensitive and selective electrochemical sensor based on surfactant modified graphene paste electrode was designed for the determination of catechol (CC) and resorcinol (RS). The developed electrodes were characterized by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and Field emission scanning electron microscopy (FE-SEM). Under the ideal conditions, CV and DPV studies revealed that, compared with bare graphene paste electrode (BGPE), sodium dodecyl sulfate modified graphene paste electrode (SDSMGPE) demonstrated an increase in the efficiency of the electrocatalytic oxidation of CC. Under the optimized condition the peak current for CC showed a good linear relationship with concentration in the range 2.0 × 10−6 to 1.0 × 10−5 and 1.5 × 10−5 to 1.5 × 10−4 M, and the detection limit was 106 nM (S/N = 3). The CV results show that CC and RS could be detected simultaneously using SDSMGPE with peak-to-peak separation of 0.728 V for CC-RS. The sensor is very promising for CC sensing attributing to its high sensitivity, fast response, excellent stability, and good reproducibility. The SDSMGPE sensor utilized for detection of CC in real sample with a satisfactory result.

Electrochemical Polymerised Graphene Paste Electrode and Application to Catechol Sensing

Objective: To build up an advantageous strategy for sensitive determination of catechol (CC), a poly (proline) modified graphene paste electrode (PPMGPE) was fabricated and used as a voltammetric sensor for the determination of CC. Methods: The performance of the modified electrode was studied using cyclic voltammetric (CV) and differential pulse voltammetric method (DPV). The modified electrode was characterized by CV and DPV. The surface of the modified electrode was examined by FESEM. The electrochemical behavior of CC in phosphate buffer solution (pH 7.5) was inspected using bare graphene paste electrode (BGPE) and PPMGPE. Results & Conclusion: The PPMGPE shows a lower limit of detection, calculated to be 8.7×10–7mol L−1 (S/N=3). This modified electrode was applied successfully for the determination of CC in water samples without applying any sample pretreatment.

Electrochemical Determination of the KRAS Genetic Marker for Colon Cancer with Modified Graphete and Graphene Paste Electrodes

ABSTRACTThe determination of KRAS was performed using electrochemical sensing devices based on graphite and graphene pastes, modified with a phthalocyanine-boron dipyrromethene (BODIPY) and azulenes dyes. The limits of quantification for KRAS were 1.54 × 10−4 µg/mL using the sensor based on the phthalocyanine-BODIPY dye and graphite, 2.64 × 10−7 µg/mL using the sensor based on 2,6-bis((E)-2-(furan-2-yl)vinyl)-4-(4,6,8-trimethylazulen-1-yl)pyridine/TiO2Pt/reduced graphene oxide, and 3.84 × 10−3 µg/mL using the sensor based on 2,6-bis((E)-2-(thiophen-3-yl)vinyl)-4-(4,6,8-trimethylazulen-1-yl)pyridine/TiO2Pt/reduced graphene oxide. Recovery measurements demonstrated the suitable analytical performance of these sensors for the early detection of colon cancer by the analysis of whole blood samples.

Silver Nanoparticle Modified Graphene Paste Electrode for the Electrochemical Detection of Lead, Cadmium and Copper

Silver Nanoparticle Modified Graphene Paste Electrode for the Electrochemical Detection of Lead, Cadmium and Copper

Voltammetric determination of lead and cadmium in vegetables by graphene paste electrode modified with activated carbon from coconut husk

A multilayer graphene paste electrode (MGPE), consisting of graphene flakes and mineral oil, was modified with activated carbon (AC). The AC was produced from coconut husk using zinc chloride as the activating agent. The AC/MGPE was fabricated by substituting an amount of the multilayer graphene (MG) with the AC, and the resulting paste was packed in a Teflon syringe. The electrode was used to simultaneously detect lead (Pb2+) and cadmium (Cd2+) via anodic stripping voltammetry (ASV). The amounts of MG and AC in the electrodes were varied by substituting the amount of the former with the latter (by percent) and the best electrode was found to consist of 5% AC and 95% MG. The optimal parameters, accumulation time, deposition time, and deposition potential were determined. The optimized parameters were used on the said best electrode to determine the calibration curve and limit of detection. The peak current had a linear relation with the concentration of the heavy metals with a correlation value (R2) of 0.9956 and 0.9973 for Cd2+ and Pb2+, respectively. After which the electrode was used to detect heavy metals in vegetable samples, and the results were verified via atomic absorption spectroscopy. The heavy metal concentrations that were detected in most of the samples were above the maximum limit as dictated by the World Health Organization.