Wave Voltammetry Method Research Articles

Anode process on gold in KF–AlF<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub> melt

In the conditions of resource saving and carbon footprint reduction, the development of oxygen–releasing anodes for technologies of production of important metals and alloys by electrolysis of molten salts seems to be an urgent task. To determine the degree of “inertness” of a particular anode material, data on the kinetics and mechanism of the anode process on a material not subject to oxidation are required. In this connection, the anodic process on gold in the KF–AlF3–Al2O3 melt for electrolytic aluminum production was investigated by cyclic and square–wave voltammetry methods. The influence of temperature (715 and 775 оC) of the melt, the content of Al2O3 in it (from 0.1 to saturation), as well as the polarization rate (0.05–1 V/s) on the kinetics and some features of the mechanism of the investigated process was determined. An assumption is made that oxygen release on gold without dissolution of the substrate takes place in the region of overvoltages from 0 to 0.8 V. It is shown that the process includes the stages of electrochemical adsorption and desorption of the intermediate product, the first of which is limited by the diffusion of electroactive anions to the anode.

Composite Material from Waste ABS 3D Filaments and Graphite: A Cost‐Effective and Sustainable Alternative for Electrochemical Sensor Manufacturing and Voltammetric Analysis of Acebutolol

AbstractAdditive manufacturing technology is renowned for its ability to produce components on demand. Presently, the development of sustainable materials has been promoted by Green Chemistry, leading to an increase in the recycling of polymers and other materials for use in 3D printing. In this work, we proposed the construction of a 3D printed electrochemical device using a conductive paste made from 3D printing residues of acrylonitrile butadiene styrene (ABS) filaments and graphite to develop a sustainable sensor for acebutolol detection using square wave voltammetry method. The electrode was characterized using imaging and electrochemical techniques, demonstrating superior electrochemical performance compared to a commercial device. The method exhibited excellent analytical performance with a linear working range from 0.98 to 51.8 μmol L−1 and good detectability (detection limit) of 0.28 μmol L−1. Furthermore, the recycled sensor demonstrated good precision with a relative standard deviation of less than 8.4 % and good accuracy with recovery percentages ranging from 93 to 107 % for monitoring acebutolol in urine and tap water samples. Additionally, the device was free from interference from the matrix and other commonly used drugs, making it suitable for electroanalytical applications and extremely promising.

Molten‐Salt‐Assisted Synthesis of Carbon‐Doped BN Nanosheets for the Sensitive Detection of Paracetamol

AbstractHigh‐performance sensors are in constant demand for health care and environmental protection. In this study, a sensitive paracetamol (PCM) sensor was designed by modifying glassy carbon electrode (GCE) with carbon‐doped boron nitride (BCN/GCE) nanosheets. The BCN nanosheets were synthesized using a molten‐salt method, which ensured the uniformity of size distribution. X‐ray diffraction and transmission electron microscopy results suggested that the carbon‐doping hardly changed the crystal structure and morphology of hexagonal boron nitride (HBN). However, the carbon‐doping can reduce the bandgap, increase the specific surface area and improve the electrical conductivity, which is attributed to the formation of abundant point defects in the BN crystal. These point defects modulate electronic structure and surface activity, and further improve the electrocatalytic properties of BN. The BCN nanosheets exhibited outstanding electrocatalytic activity in the oxidation of paracetamol (PCM). With the help of square wave voltammetry (SWV) method, the BCN/GCE demonstrated linear current response towards PCM covering the concentrations of 0.05–70 μM and 70–200 μM with a detection limit (LOD) of 0.0086 μM. The developed method also showed excellent selectivity and high stability. In addition, the BCN/GCE sensor worked well when it was applied to quantify PCM in actual samples.

Fe-doped WO3-Modified sensor for the improved electrochemical detection of curcumin

In this study, an iron-doped tungsten oxide (Fe-WO3) nanomaterialwas synthesizedand utilized to modify carbon paste electrodes for the identification of the bioactive ingredient curcumin (CUM). Turmeric contains a bioactive compound called curcumin, which is yellow and has various potential biological applications, such as being an anti-carcinogenic, anti-inflammatory, and antioxidant agent. The Fe-WO3 nanomaterial underwent characterization through SEM, XRD, and EDS techniques. The electrochemical performance of CUM was inquired using square wave and cyclic voltammetry methods. During catalytic oxidation, the Fe-WO3 working electrode assembly showed faster electron transport than the bare CPE. Investigations havebeen conductedinto the kinetics of oxidation, and the developed sensor demonstrated an excellent linear detection range (5 μM to 60 μM), a decreased limit of detection (6.2 × 10−8 M), and a limit of quantification under optimal conditions (20.7 × 10−8 M).The numbers of electrons transmitted, the heterogeneous rate constant, the electron transfer coefficient, and the electrochemical oxidation were all measured. The results from the examination of CUM in actual samples using the devised Fe-doped WO3 modified electrode were good. Additionally, it showed a considerable increase in the curcumin peak current concerning responsively, specificity, and reliability for curcumin analysis.

Validation and application of the square wave voltammetry method for the electrochemical determination of eszopiclone in pharmaceutical formulations and human biological fluids using glassy carbon electrode

A buffer solution of Britton-Robinson (B-R) pH 6.5 was utilized to validate and apply a square wave voltammetry (SWV) method for the electrochemical determination of Eszopiclone (ESP) in pharmaceuticals and biological samples. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods were employed in the initial study of the voltammetric behavior of the ESP compound. The rotating glassy carbon (GC) indicator electrode (2.0 mm2), Pt auxiliary electrode, and Ag/AgCl reference electrode were used for ESP determination. ESP was analyzed to produce a sharp reduction peak at a potential of −750 mV. The best shape and high sensitivity of SWV cathodic current for ESP, were observed using GC electrode, B-R, pH 6.5, accumulation time (tacc) of 60-second, accumulation potential (Eacc) of - 0.1 V, amplitude voltage of 150 mV, frequency of 15 Hz, scan rate of 150 mV s−1, and stirrer rate of 1000 round per minute (rpm). The electroanalytical performance of the SWV method was evaluated through study of repeatability, stability, calibration curve, recovery, and limits of detection and quantification (LOD,LOQ). Under the optimal conditions, the SWV response was linear in the range from 3 × 10−6 to 5 × 10−5 mol/L (n = 10). The SWV method achieved a LOD of 1.9 × 10-8 mol/L (7.5 ppb), and a LOQ of 6.41 × 10−8 mol L−1 (24.93 ppb). The validated SWV method was appeared the good repeatability, sensitivity and stability for the determination of ESP. It was given a very stable SWV current for 90 min, with a 0.141 % relative standard deviation (RSD%). The SWV method was applied to the determination of ESP in pharmaceutical tablets and biological samples.

Integration of Electrochemical Sensing and Machine Learning to Detect Tuberculosis via Methyl Nicotinate in Patient Breath.

Tuberculosis (TB) remains a significant global health issue; making early, accurate, and inexpensive point-of-care detection critical for effective treatment. This paper presents a clinical demonstration of an electrochemical sensor that detects methyl-nicotinate (MN), a volatile organic biomarker associated with active pulmonary tuberculosis. The sensor was initially tested on a patient cohort comprised of 57 adults in Kampala, Uganda, of whom 42 were microbiologically confirmed TB-positive and 15 TB-negative. The sensor employed a copper(II) liquid metal salt solution with a square wave voltammetry method tailored for MN detection using commercially available screen-printed electrodes. An exploratory machine learning analysis was performed using XGBOOST. Utilizing this approach, the sensor was 78% accurate with 71% sensitivity and 100% specificity. These initial results suggest the sensing methodology is effective in identifying TB from complex breath samples, providing a promising tool for non-invasive and rapid TB detection in clinical settings.

Immobilization-free and label-free electrochemical DNA biosensing based on target-stimulated release of redox reporter and its catalytic redox recycling

Herein, we demonstrate a simple, homogenous and label-free electrochemical biosensing system for sensitive nucleic acid detection based on target-responsive porous materials and nuclease-triggered target recycling amplification. The Fe(CN)63− reporter was firstly sealed into the pores of Fe3O4 nanoparticles by probe DNA. Target DNA recognition triggered the controllable release of Fe(CN)63− for the redox reaction with the electron mediator of methylene blue enriched in the dodecanethiol assembled electrode and thereby generating electrochemical signal. The exonuclease III (Exo III)-assisted target recycling and the catalytic redox recycling between Fe(CN)63− and methylene blue contributed for the enhanced signal response toward target recognition. The low detection limit toward target was obtained as 478 fM and 1.6 pM, respectively, by square wave voltammetry and cyclic voltammetry methods. It also possessed a well-discrimination ability toward mismatched strands and high tolerance to complex sample matrix. The coupling of bio-gated porous nanoparticles, nuclease-assisted target amplification and catalytic redox recycling afforded the sensing system with well-controllable signal responses, sensitive and selective DNA detection, and good stability, reusability and reproducibility. It thus opens a new avenue toward the development of simple but sensitive electrochemical biosensing platform.

Detection of Pb(II) in water via a NH2-MIL-53(Fe)@ITO electrochemical sensor

The evaluation of the concentration of Pb(II) in solution has great significance in avoiding harm to ecology health. In this work, NH2-MIL-53(Fe) modified ITO glass (NH2-MIL-53(Fe)@ITO) was utilized as an electrochemical sensor for the detection of Pb(II) in solutions. FTIR and XPS investigation disclosed that the plentiful surface –NH group on the NH2-MIL-53(Fe) should be responsible for the highly efficient and selective detection abilities of Pb(II) due to the capture and conductivity abilities. The NH2-MIL-53(Fe) was prepared by a solvothermal technique and electrophoresed on the surface of ITO glass. A square wave voltammetry (SWV) method is employed for the sensitive determination of Pb(II). The factors of the detection condition such as the pH and ion interference are also studied. The sensitivity of 16.072 μA μM−1 cm−2 in the linear range of 2–4 μM and 54.143 μA μM−1 cm−2 in the linear range of 5–17 μM, and the limit of detection (LOD) of 0.1 μM are acquired. The repeatability and reproducibility are also studied. EIS and Tafel curves are utilized to investigate the effect of temperatures on the properties of the NH2-MIL-53. This work presents a facile strategy for the preparation of NH2-MIL-53(Fe)@ITO electrochemical sensor via electrolysis, which enhances the sensitivity toward Pb(II) and shows great application potential.

Simultaneous electrochemical detection of L-dopa and hydrogen peroxide by poly (amido amine) dendrimer/poly (neutral red) modified sensor

In a biological process, hydrogen peroxide (H2O2) plays an important role as a by-product of enzymatic reactions, and levodopa (L-dopa) is crucial for the production of dopamine in living organisms. These two different chemical compounds are essential for human health, and it is important to monitor their concentration in real samples, for example in the food and pharmaceutical industries. In this research, we fabricated a poly(amidoamine)-dendrimer/poly(neutral red) (PAMAM/PNR) modified electrode and used it to simultaneously determine the electrochemical oxidation of L-dopa and the reduction of H2O2. The PAMAM/PNR-modified sensor electrode showed a linear response from 0.08 to 2400 μM for L-dopa with a LOD (lower limit of detection) of 0.026 μM (S/N = 3). In addition, the PAMAM/PNR modified electrode showed a linear response from 4.6 μM to 2208 μM for H2O2 with an LOD of 1.5 μM (S/N = 3) and using the square wave voltammetry method. The present modified sensor electrode was successfully tested in practical application with beverages and drug samples with acceptable recoveries.

Electro‐elucidation and quantification of olopatadine hydrochloride in bulk form and eye drops using modification free glassy carbon electrode with its development by different electrolytes and surfactants

AbstractThe electro‐oxidation pathway of olopatadine hydrochloride which is used in eye drops as antihistaminic agent was proposed and discussed in detail as the first time using different voltammetry methods at the modification free glassy carbon electrode surface. The oxidation process of olopatadine hydrochloride based on the presence of electro‐active tertiary amine group was irreversible. The dissociation constants were attained by the dependence of peak current and potential on the pH values. Some kinetic parameters were also estimated. Depending on the oxidation of olopatadine hydrochloride in citrate buffer (pH 5.5; 0.1 M) and sodium dodecyl sulfate (3×10−5 M) as supporting electrolyte and a modifier, respectively, sensitive, simple, accurate and inexpensive a novel square wave voltammetry method was achieved. The method was validated for linearity, precision, accuracy, ruggedness, specificity and stability. Limit of detection of 9×10−7 M in bulk form was attained. The characterized method was successfully used for routine analysis of olopatadine hydrochloride in pharmaceutical eye drops (Olohistine® and olopalite). No electroactive interferences from the inactive ingredients present in eye drops were noticed. So the proposed method does not necessitate any extraction step preceding the drug analysis. Also, the obtained data of the calibration curve and standard addition methods were compared statistically with a reported spectrophotometrically method showing no differences between them with respect to accuracy and precision, what proved the reproducibility, suitability and reliability of the described voltammetric method for assay of olopatadine hydrochloride in its formulation.

An Electrochemical Sensor of Theophylline on a Boron-Doped Diamond Electrode Modified with Nickel Nanoparticles.

Theophylline is a drug with a narrow therapeutic range. Electrochemical sensors are a potentially effective method for detecting theophylline concentration to prevent toxicity. In this work, a simple modification of a boron-doped diamond electrode using nickel nanoparticles was successfully performed for a theophylline electrochemical sensor. The modified electrode was characterized using a scanning electron microscope and X-ray photoelectron spectroscopy. Square wave voltammetry and cyclic voltammetry methods were used to study the electrochemical behavior of theophylline. The modified nickel nanoparticles on the boron-doped diamond electrode exhibited an electrochemically active surface area of 0.0081 cm2, which is larger than the unmodified boron-doped diamond's area of 0.0011 cm2. This modified electrode demonstrated a low limit of detection of 2.79 µM within the linear concentration range from 30 to 100 µM. Moreover, the modified boron-doped diamond electrode also showed selective properties against D-glucose, ammonium sulfate, and urea. In the real sample analysis using artificial urine, the boron-doped diamond electrode with nickel nanoparticle modifications achieved a %recovery of 105.10%, with a good precision of less than 5%. The results of this work indicate that the developed method using nickel nanoparticles on a boron-doped diamond electrode is promising for the determination of theophylline.

Development of square wave voltammetry method using working electrodes modified with nickel oxide and carbon black for determination of 5-hydroxymethylfurfural in honey

This work describes the development of a novel square wave voltammetry (SWV) method for the rapid and sensitive quantification of 5-hydroxymethylfurfural (HMF) in honey samples. The method employs a combination of nickel oxide and carbon black (NiO-CB) to modify lab-made screen-printed carbon electrodes (SPCEs). The adaptability of the NiO-CB/SPCE enables its potential application in detecting HMF based on electrochemical reduction, which eliminates the need for sample extraction and streamlines the analysis process. The developed SWV method exhibits suitable working ranges of 0.5–10.0 mg kg−1 for HMF in the buffer and 10.0–200.0 mg kg−1 for HMF in honey, achieving accurate and precise measurements with a limit of detection (LOD) and limit of quantification (LOQ) of 5.4 and 18.0 mg kg−1, respectively. The exceptional specificity of the developed method towards HMF is confirmed by its negligible response to interfering substances commonly found in honey. Furthermore, a comparative study between the developed SWV and the standard high-performance liquid chromatography (HPLC) methods reveals a strong correlation and no significant difference in the results obtained. Hence, the innovative electrochemical method can be utilized as an alternative method for rapidly quantifying HMF in honey samples.

Electrochemical Study of 17β-Estradiol and its Determination in Pharmaceutical Preparations using Square Wave Voltammetry

In the present study, the electroanalytical behavior of 17β-estradiol was investigated using cyclic voltammetry. The procedure was based on 17β-estradiol being electrochemically oxidized at a platinum electrode in non-aqueous solutions. At 1.47 V, the oxidation peak was noted. It was discovered that 17β-estradiol's oxidation was diffusion-controlled. Additionally, a quick and easy square wave voltammetry method was developed and validated in this work to determine 17β-estradiol in pharmaceutical preparations. The calibration curve was linear at 5 and 30 µg/mL concentrations. The precision was given by relative standard deviation and was less than 3.36%. Accuracy was given with relative error and did not exceed 2.54%. In pharmaceutical preparations, 17β-estradiol had an average recovery of 100.3%. Under the chosen experimental conditions, no interference was found. The suggested method is highly accurate and precise. Therefore, the method applies to measuring 17β-estradiol in pharmaceutical formulations.

Shape-optimized nanosized MOF-74T and CdS composite by transformation strategy for ultrasensitive detection of metabolic modulators trimetazidine

Due to the unique structure and diversified functions of metal-organic frameworks (MOFs), numerous studies on the morphology control of MOFs have been gradually carried out lately, but there are still plenty challenges. In this paper, MOF-74T was synthesized indirectly by using ZIF-67 as an intermediate through transformation strategy and control of the ligand 2,5-dihydroxyterephthalic acid (H4DOBDC) concentration. Meanwhile, CdS nanorods were introduced to change nucleation sites of MOF-74T, so that the shape-optimized tiny MOF-74T particles gathered on the surface of CdS. And the morphology of the CdS/MOF-74T composite was transformed from rhomboidal dodecahedron to rough rod-like. The ratio of CdS and MOF-74T in CdS/MOF-74T synthesis process was also optimized. The optimized composite can be applied in electrochemical sensing because more active sites are exposed, mass transfer resistance and carriers diffusion length are reduced. CdS/MOF-74T can be used for the ultrasensitive detection of metabolic regulator trimetazidine (TMZ) by square wave voltammetry (SWV) method with peak potentials at 1.0 V. The logarithm of response current and the logarithm of TMZ concentration shows a good linear relationship in the wide concentration range of 50 nM ∼ 200 μM (R2 = 0.9939), with a very low detection limit of 27.4 nM (S/N = 3). The sensor has also been applied to the TMZ detection in human urine sample, which indicates that CdS/MOF-74T has an excellent application prospect in medical research.

Electrochemical behavior of Sm(III)/Sm(II) and extraction of Sm on reactive electrode from molten LiF-BeF2

The electrochemical behavior of Sm(III)/Sm(II) in 2LiF-BeF2 (FLiBe) molten salt is studied by cyclic voltammetry (CV), square wave voltammetry (SWV), chrono amperometry (CA) and Tafel method in the temperature range of 773 to 973 K. The coexistence of Sm(III) and Sm(II) and the concentration ratio of Sm(III)/Sm(II) are determined by SWV test. The redox reaction of Sm(III)/Sm(II) couple on an inert tungsten electrode is demonstrated to be a quasi-reversible process with diffusion controlled mass transfer. The diffusion coefficients of Sm(III) and Sm(II) determined by chrono amperometry are in the range of 1.17 × 10-6 to 1.09 × 10-5 cm2 s−1 for Sm(III) and 2.49 × 10-6 to 3.90 × 10-5 cm2 s−1 for Sm(II) at 773 K to 973 K and the diffusion activation energy is 8.63 and 10.1 kJ mol−1 for Sm(III) and Sm(II) respectively. The coordination and transport characteristics of the Sm(III)-F and Sm(II)-F are also studied by the first principles molecular dynamics simulations. The Gibbs free energy of the SmF2 is calculated to be −1004.4 kJ mol−1 at 873 K by experimental data, and the standard reduction potential of E0SmF2/Sm is about −0.583 V vs E0BeF2/Be at 873 K. Thermodynamic evaluation and experimental results indicates that the metallic Sm could be extracted as M−rich SmxMy intermetallics (M = Cu, Ni, Al) from FLiBe based molten salts.

An ion imprinted electrochemical sensor based on flower‐like gold nanoparticles for the detection of trace arsenic(III) ions in water and food samples

AbstractA selective and sensitive electrode based on Au−S bonds between As(III) ion‐imprinted polymer (IIP) and the flower‐like gold nanoparticles (FL‐AuNPs) had been rationally developed for detecting As(III) by using the square wave voltammetry (SWV) method. Under optimized measurement conditions, the prepared electrochemical sensor exhibited obvious detection performance of As(III) in the range of 0.009 μg/L–0.50 μg/L with a relatively low detection limit of 0.015 μg/L. Furthermore, the imprinted electrochemical sensor displayed good reusability, excellent specificity, and demonstrated high potential for environmental control with a recovery rate between 80.7 % and 113.3 %.

A carbon based-screen-printed electrode amplified with two-dimensional reduced graphene/Fe3O4 nanocomposite as electroanalytical sensor for monitoring 4-aminophenol in environmental fluids

The analysis water pollutants are so important strategy for investigation of water quality. On the other hand, 4-aminophenol is known as a hazardous and high-risk compound for humans, and its detection and measurement is very important for investigating the quality of surface and groundwater. In this study, graphene/Fe3O4 nanocomposite was synthesized by a simple chemical method and characterized by EDS and TEM methods and results showed Nano spherical shape of Fe3O4 nanoparticle with diameter about 20 nM decorated at surface of 2D reduce graphene nanosheet (2D-rG-Fe3O4). The 2D-rG-Fe3O4 was used as excellent catalyst at surface of carbon-based screen-printed electrode (CSPE) and used as electroanalytical sensor in monitoring and determination of 4-aminophenol in waste water sample. The results confirmed improving ∼4.0 times in oxidation signal and reducing 120 mV in oxidation potential of 4-aminophenol at surface of 2D-rG-Fe3O4/CSPE compare to CSPE, respectively. The electrochemical investigation showed pH dependence behavior with equal value of electron and proton for -aminophenol at surface of 2D-rG-Fe3O4/CSPE. Using square wave voltammetry method (SWV), the 2D-rG-Fe3O4/CSPE successfully monitored 4-aminophenol in the concentration range 1.0 nM–200 μM. Finally, 2D-rG-Fe3O4/CSPE monitored 4-aminophenol in the different environmental fluids such as urban waste water, industrial waste water and river samples with recovery range 97.2%–104.3% that confirm powerful ability of 2D-rG-Fe3O4/CSPE as analytical tool.

Composite material immobilized in 3D-printed support, an economical approach for electrochemical sensing of nimesulide

This work aimed to build a disposable electrode, cheap, and robust, with a maximum manufacturing value of US$ 0.02 per sensor, whose basic structure is a composite material (CM) immobilized on 3D support of acrylonitrile butadiene styrene (ABS), to the determination of Nimesulide (NIM) in different samples. The surface characterization of the electrodes was made by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The electrochemical response for NIM obtained was compared with a commercial Glassy Carbon electrode (GCE), where a 70 % increase in the analytical response was observed. The sensor was applied for the quantification of NIM by the square wave voltammetry (SWV) method in pharmaceutical formulations, tap water, synthetic urine, and breast milk. The optimized method presented a satisfactory linear range of 10 to 50 µmol/L, with a simple sample treatment, good precision (RSD < 3.38 %), and excellent detectability (limit of detection 0.018 µmol/L). Samples were spiked at three concentration levels to evaluate the accuracy of the method, obtaining recovery values from 96.2 to 112.8 %. Thus, the disposable proposed device proves to be a promising analytical tool for routine analysis of NIM in different samples with a minimum sample preparation step (simple dilution).

Electrochemical sensor based on a ZnO-doped graphitized carbon for the electrocatalytic detection of the antibiotic hydroxychloroquine. Application: tap water and human urine.

In December 2019, the world experienced a new coronavirus, SARS-CoV-2, causing coronavirus disease 2019 originating from Wuhan.The virus has crossed national borders and now affects more than 200 countries and territories. Hydroxychloroquine has been considered as a drug capable of treating COVID-19. The objective of this work is to establish a simple platform for electrocatalytic detection of hydroxychloroquine in human urine samples and pharmaceutical samples (tablets) using a ZnO@CPE sensor constructed by simple and inexpensive hydrothermal methods using a square wave voltammetry method. The best results are obtained in a PBS electrolyte with irreversible behavior of the hydroxychloroquine complement and controlled by diffusion coupled with absorption phenomena. The ZnO@CPE shifts the oxidation potential of hydroxychloroquine with the formation of a single very intense peak at the position of Epa = 0.5V/(vs Ag/AgCl) with a shift is ΔEp = 0.1V(vs Ag/AgCl) compared to the unmodified electrode. The obtained ZnO@CPE hybrid nanocomposite was characterized by different techniques and showed excellent electrocatalytic activity and higher active surface area compared to the bare carbon paste electrode. Under the optimized experimental conditions, the ZnO@CPE sensor showed good analytical performance for the determination of trace amounts of hydroxychloroquine, a wide linearity range from 10-3M to 0.8 × 10-6M with a very low detection limit in the range of 1.33 × 10-7M, satisfactory selectivity, acceptable repeatability and reproducibility. The calculated recovery and coefficient of variation for the two samples analyzed are very satisfactory, ranging from 97.6 to 102% and 1.2 to 2.3% respectively. The proposed applied method and the fabricated sensor offer the possibility to analyze traces of hydroxychloroquine in real human urine and water samples. Strategy for the electro-oxidation reaction of hydroxychloroquine on the electro-catalytic surface of the ZnO@Carbon graphite electrode and real-time detection of hydroxychloroquine.

Electroanalytical Analysis of Guaifenesin from Pharmaceuticals on Boron Doped Diamond Electrode

The expectorant drug guaifenesin (GFN) electroanalytical analysis was performed on boron doped diamond electrode (BDDE) by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV) methods. The results of CV studies indicate that the reaction mechanism of GFN in the oxidation direction on the BDDE is irreversible and diffusion controlled. The linearity ranges are 0.400 ˗ 100 µM and 0.800 ˗ 100 µM for DPV and SWV methods, respectively. Limit of detection (LOD) values are obtained as 1.47 nM for DPV and 2.92 nM for SWV. Quantitative analysis of GFN from the pharmaceuticals was performed with fully validated DPV and SWV methods without any pre-separation. The sensitive methods with good recovery, high precision and accuracy have been developed for the electroanalytical analysis of GFN.