Carbon Paste Sensor Research Articles

An Electrospun Nanofibrous Sensor Based on a Porous (Cr/Zn) Slats Oxide for Voltammetric Detection of Ezetimibe Drug in Real Samples

AbstractHerein, a series of bimetallic slats oxide nanofibers with different molar proportions of Cr: Zn were synthesized via the electrospinning method. Nanofibers with a molar proportion of (Cr: Zn=1: 2) [CrZn3] demonstrated a large superficial area (123.3 m2/g) with minimal resistivity. A modulated carbon paste sensor (MCPS) constructed using 1.0 % of [CrZn3] exhibited remarkable surface electrocatalytic activity for oxidation of ezetimibe drug and oxidation reduction of an electroactive probe (K3[Fe(CN6)]). Under optimized conditions, the limit of the detection of the obtained MCPS for ezetimibe in bulk form was 0.024 nmol L−1 and its linear range was 0.08–1.5 nmol L−1. The sensor also demonstrated good selectivity toward the drug in human medication and serum fluid.

New analysis with a comparative study for antihistaminic Levocetirizine di-HCl in Levcet dosage form, human fluids plasma/urine with modified carbon paste sensor

New analysis with a comparative study for antihistaminic Levocetirizine di-HCl in Levcet dosage form, human fluids plasma/urine with modified carbon paste sensor

Glucose modified carbon paste sensor in the presence of cationic surfactant for mefenamic acid detection in urine and pharmaceutical samples

In this study, a novel and robust glucose modified carbon paste electrode (CPE) is developed for the ultrasensitive detection of mefenamic acid (MA). MA, a non-steroidal anti-inflammatory drug, used for its antipyretic and analgesic effects is harmful to the patient at higher dosages. MA is also listed as a chemical pollutant affecting the environment negatively. In this view, a sensitive sensor has been developed for the identification of the MA by employing a glucose modified carbon paste electrode in the presence of a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB). The developed sensing probe was characterized using various electrochemical techniques, and thereafter used to study the electrochemical nature of MA. The sensor was able to detect MA with a linear dynamic range (LDR) of 2.5 × 10−8 to 5.0 × 10−4 M, and limit of detection (LOD) of 1.01 (±0.03) nM, respectively. Interference due to co-existing molecules was found to be negligible. Real sample analysis was performed in human urine samples and pharmaceutical tablets using SWV, and higher recovery of 92.70–99.16% and 96.0–98.5% were achieved, respectively. This shows that the sensor can be further used in other biological, pharmaceutical, or environmental samples for the detection of MA.

Synthesis of thiol amine surfactant for sensor fabrication to determine chromium(III) ions in different water samples

A thiol amine surfactant, poly-3-(dodecylthio)-N-hexadecylacrylamide (iphI) was prepared and characterized using spectral methods of analyses. The proposed potentiometric method was based on the fabrication of iphI-modified carbon paste (iphI-MCPE; electrode IV) sensor. Fast, highly sensitive and wide dynamic range potentiometric sensor was constructed using the prepared ionophore to quantify Cr(III) ions in spiked water sample under optimum conditions. The electrode (IV) exhibited an excellent Nernstian response to Cr(III) ion ranging from 4.8 × 10-7 to 1.0 × 10-2 mol L-1 with a detection limit of 4.8 × 10-7 mol L-1 and a slope of 19.59±0.45 mV decade-1 over a wide pH range (2.0-8.0) with a fast response time (7 s) at 25 oC. The proposed sensor showed fairly good discriminating ability towards Cr(III) ion in comparison with many hard and soft metal ions. The developed electrode has been successfully applied for the Cr(III) ions potentiometric determination in different water samples. The results obtained compared well with those obtained using atomic absorption spectrometry.

A simple and low-cost poly (dl-phenylalanine) modified carbon sensor for the improved electrochemical analysis of Riboflavin

The current study reports on the electroanalysis of Riboflavin (RF) on the surface of a poly dl -phenylalanine modified carbon paste sensor (PDLPAMCPS). The developed sensor caused a noticeable electrocatalytic action for the redox activity of RF in a phosphate buffer solution (PBS) of pH 6.5. This analysis was evaluated using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. The active surface of the functioning sensor exposes well developed anodic peak with prominent electron transfer. PDLPAMCPS shows distinctive and improved DPV and CV peaks for RF with and without the presence of organic dyes and dopamine (DA). The impact of the solution pH, scan rate, accumulation potential and concentration on RF at PDLPAMCPS were studied. A vibrant linear growth was observed between the oxidation peak current and the RF concentration in the range of 6.0 μM–30.0 μM, which provides a lower limit of detection (LOD) of 92 nM with excellent sensitivity. The proposed method and sensor were applied for the assessment of RF in medicine sample as an analytical application with fine recoveries and low LOD. • A simple and low-cost carbon sensor was designed using poly ( dl -Phenylalanine) for the sensing of Riboflavin. • Prepared sensor was characterized by CV, DPV, EIS and FE-SEM analysis. • Equipped sensor shows high sensitivity, selectivity and lower LOD of 92 nM towards Riboflavin detection. • Interference effect on prepared sensor for Riboflavin was studied.

Solubility and thermodynamic studies of sparingly soluble tellurite salts

In the past few years, tellurium has attracted much attention as it is widely used in a large number of important industrial applications. Despite its importance, there is a lack of data on its salts in the literature. In this study, different sparingly soluble tellurite salts (e.g., Ag2TeO3, PbTeO3, CaTeO3, SrTeO3 and BaTeO3) were prepared and characterized using various techniques including powder X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectrometry, Fourier transform infrared spectroscopy and thermogravimetric analysis as well as differential scanning calorimetry. Moreover, the solubility and solubility product of these salts are studied by potentiometric method using carbon paste sensors. By applying standard and double standard addition methods, the tellurite ion content in the supernatant liquid (TeO32− ) was determined at 25 °C. The solubility products were confirmed by atomic absorption spectroscopy and complexometric titrations, which indicate the high sensitivity and accuracy of the proposed potentiometric method. In addition, thermodynamic parameters such as Gibbs free energy ∆G°, enthalpy ∆H° and entropy ∆S° of the dissociation process or solution were calculated using the Debye–Huckel equation via the determination of solubility of metal tellurite salts at different temperatures.

Preparation and characterization of novel MWCNTs/Fe-Co doped TNTs nanocomposite for potentiometric determination of sulpiride in real water samples

Novel multiwalled carbon nanotubes/ Fe-Co doped titanate nanotubes nanocomposite (MWCNTs/Fe-Co doped TNTs) facilitated the charge transfer and enhanced sensitivity and selectivity. Herein, three novel modified carbon paste sensors (CPSs) based on MWCNTs (sensor I), Fe-Co doped TNTs (sensor II) and MWCNTs/Fe-Co doped TNTs composite (sensor III) were fabricated for a simple, low cost and high accuracy electrochemical method for the potentiometric determination of sulpiride (SLP). The sensors exhibited excellent Nernstian slopes 57.1 ± 0.4, 56 ± 0.5 and 58.8 ± 0.2 mV decade−1 with detection limits (DL) 7.6 × 10−7, 1.58 × 10−6 and 8.7 × 10−8 mol L−1, quantification limits (QL) 2.5 × 10−6, 5.2 × 10−6 and 2.9 × 10−7 mol L−1 for a long lifetime 20, 18, and 25 weeks for sensors (I), (II), and (III), respectively. The modified sensor (III) was applicable by measuring the concentration of spiked SLP in pure solutions, pharmaceutical products, human urine, and real water samples. The proposed method can be used as an important analytical tool in the quality control of the pharmaceutical industry.

Electrochemical determination of verapamil hydrochloride using carbon nanotubes/TiO2 nanocomposite based potentiometric sensors in surface water and urine samples

This study aims to apply a current progress on the construction and sense of carbon paste sensors based on carbon nanotubes (CNTs)/ TiO2 nanocomposite for verapamil hydrochloride determination. The role affecting the behavior of ionophore, lipophilic anionic additive as well as plasticizer is discussed carefully. The developed sensors were abbreviated as β-CDCPE and VER-PTCPE. These sensors exhibited excellent Nernstian behavior with linear dynamic ranges of 6.2 × 10−7 – 1.0 × 10−2 and 7.4 × 10−7 – 1.0 × 10−2 mol L − 1, detection limits 2.0 × 10−7 and 3.5 × 10−7 mol L − 1 and quantification limits 6.6 × 10−7 and 1.1 × 10−6 mol L − 1 for β-CDCPE and VER-PTCPE, respectively. The investigated sensors showed adequate selectivity toward the target ion against some inorganic cations, neutral species and Diltiazem hydrochloride (drug with similar structure). The proposed potentiometric sensors were successfully performed for drug determination in pharmaceutical products, spiked surface water and human urine samples with good recovery data (98.46 and 99.06) for β-CDCPE and VER-PTCPE, respectively.

Application of PVC Membrane and Modified Carbon Nanotubes Paste as Electrochemical Sensors for Potentiometric Determination of Loperamide Hydrochloride

Objectives: The main purpose of this work is to design a simple, sensitive, accurate and precise potentiometric membrane ion selective electrodes for selective determination of loperamide hydrochloride in bulk powder and in pharmaceutical preparation. Methods: Electrochemical behavior of loperamide hydrochloride were investigated using PVC membrane and modified carbon nanotubes paste sensors. The linearity of this developed method was established in the concentration range of 10-5 - 10-2 M and10-6 - 10-2 M shows a Nernstian slope of 57.38 mV and 58.74 mV for PVC and Carbon paste sensor, respectively. Results: Validation parameters such as specificity, linearity, accuracy, precision, stability, limit of detection were found to be within the acceptance limit as studied according to IUPAC recommendation data. Conclusion: Both sensors are successfully applied for potentiometric determination of loperamide hydrochloride in its pure form and pharmaceutical formulations.

Facile caffeine electrochemical detection via electrodeposited Ag nanoparticles with modifier polymers on carbon paste sensor at aqueous and micellar media

The analysis and detection of caffeine (Caf) is very useful due to its widespread usage in several daily consumed beverages, food products, and pharmacological preparations with various physiological effects. The preparation of a newly electrodeposited Ag nanoparticles – cellulose acetate phthalate (CAP) – chitosan (Chit) modified carbon paste (ACCMCP) sensor for sensitive determination of Caf in 0.01 mol L−1H3PO4solution (pH 1.0–5.0) both in aqueous and micellar media (0.5 mmol L−1SDS) was achieved. The interaction of Caf was monitored using electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and chronoamperometry, and surface characterization was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray techniques. The linear detection range of Caf was between 4 and 500 μmol L−1(r2= 0.955) and the limit of detection obtained from the calibration plot was 0.252 μmol L−1. The sensor was applicable for detecting Caf in numerous real samples with recoveries from 98.03% to 101.60% without interference of any accompanying species, which ensures high method selectivity.

Economical Approach for Determination of Kojic Acid by Nanostructured Ionic Liquid-Based Carbon Paste Sensor

An economical and sensitive nanostructured sensor based on carbon paste electrode (CPE) for the determination of kojic acid (KA) was developed in the current work. The applied CPE was modified with 1-butyl-3-methylimidazolium tetrafluoroborate (1B3MITFB) as a conductive binder and NiO nanoparticles (NiO/NPs). The proposed modified ionic liquid-based carbon paste electrode showed satisfactory concentration range and lower detection limit of 5.0–600 μM and 0.8 μM at phosphate buffer pH 6.0, respectively. An acceptable reproducibility with a satisfactory analytical characteristic was observed for the proposed sensor in the presence of common interfering compounds. The observed irreversible oxidation behavior of KA at the surface of the NiO/NPs/1B3MITFB/MCPE was controlled under the diffusion step and the diffusion coefficient (D) at the mass transport limited rate found to be 2.3 × 10−4 cm2 s−1. According to the slope of the Tafel plot, the value of 0.625 was calculated for the electron transfer coefficient (α). The acquired data from electrochemical impedance spectroscopy studies confirmed that the presence of NiO NPS and 1B3MITFB as a conductive binder resulted in a significant increase in the electro-oxidation signal of KA. The value of 12.3 kΩ for the Rct of unmodified CPE decreased to the value of 1.7 kΩ for the modified electrode. The obtained results revealed that the proposed modified ionic liquid-based carbon paste electrode could be applied successfully for the analysis of trace amounts of KA in biological samples such as blood serum, urine, and pharmaceutical samples such as liposome carriers containing KA as well as food samples such as vinegar. The synthesized NiO nanoparticles were characterized using XRD and EDAX analyses. The morphology of NiO/NPs is further characterized by SEM.

Highly efficient and selective quantification of vanillin in food, beverages and pharmaceuticals using surfactant modified carbon paste sensor

The rampant use of vanilla has severe ramifications on our health. Federal Office of Public Health has placed restrictions on use of Vanillin (VAN) in baby food. Our aim was to prepare a sensor for the swift determination of VAN in food essence, non-alcoholic beverages, food supplements and pharmaceutical formulations. A modified carbon paste electrode drop cast with cetyltrimethylammoniumbromide (CTAB) was designed and scrutinized by cyclic and differential pulse voltammetry techniques. Surface morphology was studied using Field emission scanning electron microscopy (FE-SEM), the elemental composition by Energy Dispersive X-rays (EDX), and charge transfer kinetics by Electrochemical Impedance Spectroscopy (EIS). A significant decline of 153 mV in anodic overpotential with an impressive eight-fold enhancement of current indicates better electrocatalytic kinetics at the modified electrode. The calibration curve exhibited linearity over a wide range of 8 × 10−8 to 3 × 10−3 M, with a limit of detection 0.23 nM (S/N = 3). The selectivity of the fabricated sensor towards VAN in the presence of 1000-fold excess of common interferants such as ferulic acid, folic acid, tryptophan, and uric acid was noteworthy.

The use of optical and atomic force microscopy for probing the sensing mechanism of hazardous tellurium species for environmental applications

Determination of tellurium compounds is of particular interest because of the intrinsic toxicity associated with its water-soluble oxyanions, tellurite TeO32−. Among various analytical approaches, carbon paste sensors (CPSs) are widely used for the determination of heavy metals, nucleic acids and other organic compounds due to their simplicity, sensitivity and cost-effectiveness. In this study, chemically modified carbon paste sensor is developed for the analysis of tellurite ions in pure and in real samples. The sensor showed nearly Nernstian behavior (30 mV) with wide linear range and low detection limit. Moreover, the sensor was successfully applied to the determination of tellurite in environmental and biological samples such as wastewater, human serum, tellurite culture media, synthetic tellurite-cefotaxime and tellurite/tellurate mixtures. The results show high recovery rates, selective and highly reproducible response, indicating the suitability of the proposed sensor for practical applications. In addition, we studied how several parameters such as the type of carbon, type of the plasticizer, amount of the modifier and composition of the sensor affect its electrochemical performance. This was achieved by tracing the morphology and composition of the electrode using optical and atomic force microscopy. The combination of these techniques provides valuable information on the physical, mechanical and chemical properties of the sensor, which proved to be very helpful in understanding its behavior under different chemical conditions. The study also gives some insights on the optimization of chemical sensors based on chemically modified carbon paste sensors.

Voltammetric detection of caffeine in pharmacological and beverages samples based on simple nano- Co (II, III) oxide modified carbon paste electrode in aqueous and micellar media

Caffeine (Caf) is one of the most widespread compounds in food components, beverages and medicines, which drives us to find a simple, fast and convenient method for its determination. The promising Nano-Cobalt (II, III) oxide modified carbon paste (NCOMCP) sensor was fabricated and applied to the sensitive determination of Caf in both aqueous (0.01 mol L−1 H2SO4) and micellar media (0.5 mmol L−1 sodium dodecylsulfate, SDS). Surface characterization was performed utilizing scanning electron microscopy (SEM) and energy dispersive analysis of X-rays (EDX). The electrochemical behavior of Caf was studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). From these experiments, the apparent diffusion coefficient (Dapp) and catalytic rate constant (kcat) were evaluated to be 4.2 × 10-5 cm2 s-1 and 1.92 × 103 mol−1 L-2 s-1, respectively. Caf can be detected in a concentration range between 5.0 and 600 μmol L−1, with a limit of detection (LOD) of 0.016 μmol L−1, as determined from the calibration plot obtained using differential pulse voltammetry (DPV). The sensor was applicable for Caf sensing in several commercial real samples with recoveries ranging from 98.9% to 101.9%. It exhibited good selectivity in the presence of common interferences.

May glutathione and graphene oxide enhance the electrochemical detection of caffeine on carbon paste sensor in aqueous and surfactant media for beverages analysis?

Detecting Caffeine (CAF) is indispensable issue due to its widespread in several daily consumed beverages, food products and pharmacological preparations having various physiological effects. A novel graphene oxide-reduced glutathione modified carbon paste (GORGCP) sensor has been built on for sensitive determination of CAF in 0.01 M phosphoric acid (H3PO4) solution of pH range (1.0–5.0) in both aqueous and surfactant media (0.5 mM sodium dodecylsulfate (SDS)) was achieved. The interaction of CAF over the surface of sensor was monitored utilizing various electrochemical techniques like cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Chronoamperometry (CA), while surface characterization of electrode was performed utilizing scanning electron microscope (SEM) and energy dispersive x-ray techniques (EDX). The linear detection range of CAF was between 8 – 800 μM (r2 = 0.9676) and the limit of detection (LOD) obtained from the calibration plot was 0.153 μM. The sensor was applicable for detecting CAF in numerous real samples with recoveries of 97.76% to 101.36% without interference of any accompaning species, which ensures high selectivity and sensitivity.

A voltammetric carbon paste sensor modified with NiO nanoparticle and ionic liquid for fast analysis of p-nitrophenol in water samples

p-Nitrophenol is a water pollutant with wide applications in petrochemistry, synthesis of dyes and pesticides. The material has however been reported to harmful effects on humans. Accordingly, the present work focused on developing a voltammetric sensor for the determination of p-nitrophenol using a modified carbon paste electrode (CPE) as the working electrode. The modification of the CPE was performed using NiO nanoparticles (NiONPs) and N-hexyl-3-methylimidazolium hexafluorophosphate (NH3MPF6). The resulting sensor showed very good performance in the analysis of p-nitrophenol in water samples. MAP, energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscopy (AFM), UV–vis and field emission scanning electron microscopy (FESEM) analyses confirmed the presence of high-purity NiONPs with a diameter size of 22.0 nm in the modified electrode. It was concluded that NiONPs and NH3MPF6 act as high-performance modifiers in the working electrode matrix and hence create a voltammetric sensor for nano-molar determination of p-nitrophenol. Validation of the applicability of the sensors was performed through the determination of p-nitrophenol in different water samples, and the results indicated respective LDR and LOD values of ~0.01–280 μM and ~7.0 nM for p-nitrophenol.

Voltammetric detection of chlorite ion using carbon paste sensor modified with N-cetylpyridinium–bentonite

ABSTRACTA voltammetric carbon paste sensor (CPS) was described for the detection of chlorite ion in water analysis. For the construction of the voltammetric CPS, organo-bentonites were synthesised by intercalation of N-cetylpyridinium (NCP) at different amounts into interlayer gap of bentonite. Some features of the obtained organo-bentonites such as structural, thermal and morphological were investigated by using various techniques. Afterwards, the voltammetric behaviour of the solution was investigated with cyclic voltammetry in the potential range of 0.0–1.0 V at a scan rate of 50 mV s−1 based on the obtained organo-bentonites as electroactive material. The characterisation of the prepared organo-bentonites as electroactive material, the effect of the amount of NCP–bentonite (NCP–B) in modified CPS on the 10.0 mM response was tested by chancing the percentage of NCP–B in the range of 2.50–12.50% under identical experimental conditions. The pH of the measurement cell was optimised by using 0.04 M Britton–Robinson buffer in the range of pH 2.0–12.0. Under the optimised conditions, developed sensor exhibited a linear response in the range of 2.0 × 10−5 to 2.0 × 10−4 M chlorite ions concentrations. The detection limit and the limit of quantification were figured out as 6.0 × 10−6 and 2.0 × 10−5 M, respectively. The repeatability and reproducibility of the sensor were calculated as 5.0% and 6.8% (N = 5), respectively. Finally, the sensor was successfully applied for the analysis of bottled water, and the mean recovery was found as 103 ± 3%.

Potentiometric sensor based on novel flowered-like Mg-Al layered double hydroxides/multiwalled carbon nanotubes nanocomposite for bambuterol hydrochloride determination

Nowadays, development of highly efficient potentiometric sensors attracts the attention of many researchers over the world; due to the great expansion of portable analytical devices. This study aims to apply a current development to the construction and sense of carbon paste sensors based on flowered-like Mg-Al layered double hydroxides/multiwalled carbon nanotubes (FLLDH/MWCNTs) (sensor І), FLLDH/titanate nanotubes (TNTs) (sensor ІІ) and MWCNTs/TNTs (sensor ІІІ) nanocomposites for bambuterol hydrochloride analysis; to enhance the potentiometric response towards determination of the drug. The sensors exhibited excellent Nernstian slopes 58.8 ± 0.5, 58.5 ± 0.8 and 57.4 ± 0.7 mV/decade with linear working ranges of 1.0 × 10−7–1.0 × 10−2, 1.0 × 10−6–1.0 × 10−2 and 1.0 × 10−7–1.0 × 10−2 mol L−1, detection limits 2.3 × 10−8, 2.5 × 10−7and 7.5 × 10−8 mol L−1 and quantification limits of 7.6 × 10−8, 8.3 × 10−7and 2.5 × 10−7 mol L−1 for sensor І, ІІ and ІІІ, respectively. The selectivity behaviour of the investigated sensors was tested against biologically important blood electrolytes (Na+, K+, Mg2+, Ca2+). The proposed analytical method was successfully applied for BAM determination in pure drug, pharmaceutical products, surface water, human plasma and urine samples with excellent recovery data (99.62, 99.10 and 98.95%) for the three sensors, respectively.

Electro oxidation and analytical applications of valacyclovir at reduced graphene oxide modified carbon paste electrode

Abstract Electrochemical investigation of valacyclovir (VCH), an antiviral drug was investigated at carbon paste sensor modified with reduced graphene oxide (rGO/CPE). Cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques are inherited to determine the electrochemical behavior of VCH. Modified and bare carbon surfaces were characterized by Atomic force microscope (AFM). The technique dependence on current, potential, supporting electrolyte pH, concentrations, sweep rate, and excipients were evaluated to optimize the experimental conditions. Contrasted with prior reports, this study is very impressive on account of modifiers utilized and expedient because of its affectability, selectivity and LOD value.

Electroanalysis of an antihistamine drug at nano structured modified electrode

Abstract A nano level voltammetric sensing method has been developed for electrochemical analysis of cetirizine at nano clay modified carbon paste sensor by employing cyclic voltammetry and square wave voltammetry techniques in pH 8.0. The modified carbon particles were characterized by Atomic force microscope. The influence of parameters like pH, accumulation time for cetirizine drug were studied by employing cyclic voltammetry and scan rate, excipients, cetirizine concentration variation were studied by employing SWV technique for quantitative determination in phosphate buffer. The fabricated sensor was employed for the determination of cetirizine in pharmaceutical samples. The linear response was obtained in the range of 0.1 to 0.3 µM with a detection limit of 8.48 nM at nano clay modified carbon paste sensor. A possible mechanism of electrochemical oxidation of cetirizine was proposed.