Differential Pulse Voltammetry Method Research Articles

Proximate white light-long phosphor emission and a photoelectrochemical probe from boron defects engineered carbon-nitride nanosheets

A recent surge in the study of a room temperature afterglow nanomaterial has surfaced. Considering its natural coverage of a wide emission spectrum and long afterglow with single light excitation have tinkled many multidisciplinary applications. A synthesis of nanosheets with white light phosphorescence at room temperature is arduous. The manuscript emphasizes on the photoelectrochemical response of room temperature proximate white light phosphorescence in boron carbon nitride nanosheets (BCNs), synthesized at consistent physical operands by varying the overall boron dopant. The study thus envisages the interplay of the participating precursors unfolding the physio-chemical interactions between boron/carbon and nitrogen needed towards the phosphorescence phenomenon. BCNs have provided an immense physio-chemical link between the analyte and photoanode under illuminated conditions, as found vital to achieve the reported sensitivity. Three varying boron conditions are examined, out of which, a 1:4 ratio (BCN-2) is distinguished for remarkable afterglow duration. In addition, the as-synthesized BCN-2 has been used for the photo-electrochemical detection of H2O2 via a differential pulse voltammetry method with a limit of detection of 25 nM. The after-glow property has shown a remarkable response toward H2O2 detection. The easy synthesis and reproducibility of these organic phosphors also prompt its propensity to replace commercially available toxic phosphors.

Highly dispersed Cu and Ni nano cluster sensor for ultrasensitive electrochemical detection of antiviral drug lamivudine.

The accurate and rapid detection for the nucleoside reverse transcriptase inhibitor lamivudine (LAM, 3TC) in cellular systems is always a challenge in the clinic application. Here, a sensitive Cu and Ni nano cluster sensor for LAM is generated underhydrothermal conditions.TheCu and Ni atoms are highly dispersed and aggregated in the nanosized opening pore windows of the synthesized LTA zeolite, through the diatomic synergistic contribution of Cu and Ni and the enrichment of zeolitic channel pores. Using differential pulse voltammetry (DPV), the detection limit (LOD) of LAM at the potential (- 0.15V) can reach 0.001pM and the linear range is 0.002pM-0.002μM. Since the nano cluster is separated and restricted by the nanosized windows of the zeolite framework, the sensor provideshigh stability, good recovery (92.5-109%) and RSD (0.8-3.2%) in the analysis oftap water, RPMI 1640 medium, and rabbit serum. The Cu/Ni/LTA zeolite-modified glassy carbon electrode (Cu/Ni/LTA/GCE) exhibits excellent catalytic performance for LAM with high selectivity over potentiallyinterfering agents. A sensitive Cu and Ni nano cluster sensor for LAM is generated in the hydrothermal condition that the Cu and Ni atoms are highly dispersed and aggregated in the nanosized opening pore windows of the as-synthesized LTA zeolite. Through the diatomic synergistic contribution of Cu and Ni and the enrichment of zeolitic channel pores, the observed limit of detection (LOD) can reach 0.001 pM under differential pulse voltammetry (DPV) method with a wide linear relationship to 0.002 μM.

Selective and quantitative recovery of sulfadiazine from seawater by Sb doped LTA zeolite electrochemical sensor

The sensitive Sb probe has been anchored in the LTA (Linde Type A) zeolite to form a bifunctional sensor for the electrochemical detection and recycling of sulfadiazine (SDZ) in seawater. Under Amperometric i-t Curve (A i-t C) method, SDZ is quantitatively adsorbed on the Sb LTA zeolite electrode from seawater by adjusting the reduction time and potential. Under differential pulse voltammetry (DPV) method, a characteristic peak is observed at ca. 0.80 V whose intensity can indicate the SDZ concentration on the novel modified electrode. Also, SDZ can be selectively released to phosphate-buffered saline (PBS) in the potential range of 0.80–0.95 V. The electrochemical mechanism of the reversible recovery reaction is carefully studied by the cyclic voltammetry (CV) method and confirmed by the X-ray Photoelectron Spectroscopy (XPS) analysis results related to the interaction between the electrode material and SDZ before and after electrochemical process. Sb doped on LTA zeolite presented a cubic phase from SEM images, and there are some SDZ particles accumulated and adsorbed on the surface of the crystal from TEM images. Theoretical calculation results reveal that SDZ is stable in the electrochemical adsorption and desorption process due to the interaction between the SDZ molecules and the 8-ring opening windows of LTA zeolite framework. The transfer efficiency of SDZ could reach 9.62 μg / 100 s or 0.430 g / 1 g based on the mass of Sb probe. The multifunctional sensor suggests a novel strategy for the electrochemically controlled detection and recovery toward antibiotic sulfadiazine.

Fabrication of ZnWO4/Carbon Black Nanocomposites Modified Glassy Carbon Electrode for Enhanced Electrochemical Determination of Ciprofloxacin in Environmental Water Samples

The major problem facing humanity in the world right now is the sustainable provision of water and electricity. Therefore, it is essential to advance methods for the long-term elimination or removal of organic contaminants in the biosphere. Ciprofloxacin (CIP) is one of the most harmful pollutants affecting human health through improper industrial usage. In this study, a zinc tungsten oxide (ZnWO4) nanomaterial was prepared with a simple hydrothermal synthesis. The ZnWO4/Carbon black nanocomposites were fabricated for the determination of CIP. The nanocomposites were characterized by field emission scanning electron microscopy, energy dispersion X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Electrochemical studies were done using cyclic voltammetry and differential pulse voltammetry methods. Based on the electrode preparation, the electrochemical detection of CIP was carried out, producing exceptional electrocatalytic performance with a limit of detection of 0.02 μM and an excellent sensitivity of (1.71 μA μM-1 cm-2). In addition, the modified electrode displayed great selectivity and acceptable recoveries in an environmental water sample analysis for CIP detection of 97.6% to 99.2%. The technique demonstrated high sensitivity, selectivity, outstanding consistency, and promise for use in ciprofloxacin detection. Ciprofloxacin was discovered using this brand-new voltammetry technique in a water sample analysis.

Fabrication of a sensitive electrochemical sensor based on hybrid polyamide/chromotropic acid nanofibers electrospun on glassy carbon electrode for Hg2+ sensing in drinking water and canned fish samples

In this study, a new electrochemical sensor was designed based on a hybrid of polyamide (PA) and chromotropic acid (CA) nanofibers electrospun on a glassy carbon electrode (GCE) configured as PANFs-CANFs/GCE. The electrochemical response of this sensor showed an excellent electrochemical activity for the detection of Hg2+ ions using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The proposed sensor exhibited the prominent electrocatalytic value of (α = 0.60, Log Ks = 3.45 s−1 and Γ = 3.30 × 10 -9 mmol/cm2) as a result of PANFs-CANFs/GCE response to Hg2+ ions. The recommended sensor also demonstrated a linear portion in the calibration curve over the concentration range of 30 to 450 nM with the limit of detection (LOD) and limit of quantitation (LOQ) of 9.98 nM and 29.97 nM, respectively. The fabricated sensor revealed reproducible and repeatable responses with a high level of stability. Therefore, we highly recommend this new electro-spun based sensor for quantifying Hg2+ in drinking water and canned fish samples with the accurate and precise results and no side interferences.

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.

One-step synthesis of calcium-doped copper oxide nanoparticles as an efficient bifunctional electrocatalyst for sensor and supercapacitor applications

In this work, a facile and cost-effective coprecipitation method was used to synthesize calcium-doped copper oxide (Ca@CuO) nanoparticles for electrochemical detection of antipsychotic drug perphenazine (PPZ) and symmetric supercapacitor (SSC) applications. Various spectroscopic techniques were employed to analyze the structural and morphological properties of Ca@CuO. The electrochemical behavior of PPZ at Ca@CuO modified screen-printed carbon electrode (SPCE) was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The modified Ca@CuO/SPCE under optimized DPV response showed good linearity to PPZ concentrations in the range of 0.025–996.85 μM with a low limit of detection (LOD) of 0.0074 μM. Moreover, the developed sensor demonstrated good selectivity, stability, repeatability, and reproducibility. The real sample analysis of PPZ using the sensor was examined in biological samples with applicable recoveries. More interestingly, the pseudocapacitive type Ca@CuO/NF delivered an excellent specific capacitance of 314.4 F g−1 at 0.2 A g−1 and good stability with 92.7 % retention for 5000 cycles. In addition, the fabricated Ca@CuO//Ca@CuO SSC device displayed an energy density of 11.33 Wh kg−1 at a power density of 399.8 W kg−1. According to these results, Ca-doped metal oxide can be used as an efficient electrocatalyst for sensor and supercapacitor applications.

Application of Screen Printed Diamond Electrode, Coupled with “Point-of-Care” Platform, for Nanomolar Quantification of Phytonutrient Pterostilbene in Dietary Supplements: An Experimental Study Supported by Theory

Herein, a screen–printed diamond electrode (SPDE) coupled with a “point-of-care” platform (30 µL-drop concepts, single-drop-detection approach) was successfully applied for the electrochemical determination of pterostilbene (PTS). Cyclic voltammetry identified irreversible oxidation of PTS, where oxidation peak was shown to be strongly dependent on the pH of the working environmental. Although the proposition of the detailed electrochemical oxidation mechanism of PTS goes out of the scope of the present research, we have determined the most probable reactive site of our analyte, by utilizing DFT-based reactivity descriptors (Fukui functions). For electrochemical quantification of PTS, oxidation peak at 0.32 V (vs. Ag/AgCl) was followed in presence of 0.5 mol L−1 of Briton–Robinson buffer solution (pH = 9). Coupled with the optimized parameters of differential pulse voltammetry (DPV), SPDE detected PTS in two linear ranges (first range was from 0.011 to 0.912 µmol L−1; second range was from 0.912 to 4.420 µmol L−1), providing the LOD and LOQ on a nanomolar level (3.1 nmol L−1 and 10.0 nmol L−1, respectively). The selectivity of the optimized DPV method was found to be excellent, with the current changes of less than 7%, in the presence of ten times higher concentrations of the certain interferences. The practical applicability of the SPDE and single-drop-detection approach in dietary supplements (with a declared PTS content of 50 mg/tablet), with the recovery values ranging from 95 to 102%, shows that the developed method has high potential for precise and accurate PTS detection, as well as exceptional miniaturization possibilities of relevant equipment for on-site sensing.

Simple synthesis of MOF-derived Zn, Co electrocatalyst for sensitive detection of digoxin in urine sample

Digoxin is one of steroid as cardiac glycoside that is commonly used to treat congestive heart failure and arrhythmias. These steroids are toxic and carry a risk of digoxin medication overdose, even though the short therapeutic range of 2 ng/mL, and an excess of digoxin in blood plasma can reason for intoxication. It's crucial to gauge how much of the digoxin is present in the body. Therefore, a simple and accurate approach for closely monitoring digoxin in blood levels is required to minimalize the danger of toxicity. In this paper, the simple voltammetry method was used to detect the digoxin based on MOF derived zinc cobalt catalyst. First, ZnCo-MOF electrode material was synthesized using coprecipitation followed by calcination. The prepared materials were characterized with XRD, FTIR, XPS, FESEM, and TEM. By cyclic voltammetry (CV), Electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV) method was discovered for electrochemical response. The present sensor shows the low detection limit of 0.0046 ng/mL. The film exhibited good sensor preparation, repeatability and reproducibility as well as good stability for the determination of DIG. The practical applicability of sensor was investigated in urine real sample with acceptable recovery.

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%.

Direct Determination of Peroxide Explosives on Polycarbazole/Gold Nanoparticle-Modified Glassy Carbon Sensor Electrodes Imprinted for Molecular Recognition of TATP and HMTD.

Since peroxide-based explosives (PBEs) lack reactive functional groups, they cannot be determined directly by most detection methods and are often detected indirectly by converting them to H2O2. However, H2O2 may originate from many sources, causing false positives in PBE detection. Here, we developed a novel electrochemical sensor for the direct sensitive and selective determination of PBEs such as triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) using electrochemical modification of the glassy carbon (GC) electrode with PBE-memory polycarbazole (PCz) films decorated with gold nanoparticles (AuNPs) by cyclic voltammetry (CV). The prepared electrodes were named TATP-memory-GC/PCz/AuNPs (used for TATP determination) and HMTD-memory-GC/PCz/AuNPs (used for HMTD detection). The calibration lines of TATP and HMTD were found in the concentration range of 0.1-1.0 mg L-1 using the net current intensities of differential pulse voltammetry (DPV) versus analyte concentrations. The limit of detection (LOD) commonly found was 15 μg L-1 for TATP and HMTD. The sensor electrodes could separately determine intact TATP and HMTD in the presence of nitro-aromatic, nitramine, and nitrate ester energetic materials. The proposed electrochemical sensing method was not interfered by electroactive substances such as paracetamol, caffeine, acetylsalicylic acid, aspartame, d-glucose, and detergent (containing perborate and percarbonate) used as camouflage materials for PBEs. This is the first molecularly imprinted polymeric electrode for PBEs accomplishing such low LODs, and the DPV method was statistically validated in contaminated clay soil samples against the GC-MS method for TATP and a spectrophotometric method for HMTD using t- and F-tests.

Molten salt-assisted synthesis of C-TiN nanocomposites for sensitive dopamine determination

• Carbon coupled TiN nanocomposite was prepared by a molten salt method. • C-TiN exhibited enhanced electrocatalytic activity toward dopamine redox. • C-TiN/GCE displayed superior analytic performance for dopamine assay. • The method was successfully applied for dopamine detection in human serum. This work demonstrates a facile molten-salt synthesis of carbon-titanium nitride (C-TiN) nanocomposites. The C-TiN nanoparticles showed excellent electrocatalytic activity and thus were employed for the electrochemical determination of dopamine (DA). By using a differential pulse voltammetry (DPV) method, a C-TiN modified glassy carbon electrode (C-TiN/GCE) presented a high sensitivity (9620 µA·µM·cm -2 ) in the determination of DA and its detection limit (LOD) was 0.03 µM (S/N=3). Moreover, the C-TiN/GCE sensor was used to detect DA in human serum, and acceptable recoveries were obtained.

GPC3 Electrochemical Aptasensor Based on Pd-Pt NPs@ RGO-H Nanozyme to Catalyze Silver Deposition

Pd-Pt NPs@RGO-H nanozyme with good peroxise-like properties, high electrical conductivity, and high specific surface area was prepared. The nanozyme was combined with Glypican-3 aptamer (GPC3Apt) to form a signal probe. Another GPC3Apt was employed as a capture probe, and it was incubated on the surface of the screen-printed electrode that had been plated with Au NPs@rGO. To catalyze silver deposition, a sandwich-type electrochemical aptasensor based on Pd-Pt NPs@RGO-H nanozyme was built in the presence of GPC3 protein. When hydrogen peroxide and silver nitrate were added to the surface of the electrochemical aptasensor, Pd-Pt NPs@RGO-H can effectively catalyze the deposition of silver ions (Ag+) on the electrode surface to elemental silver (Ag0) due to its peroxise-like properties. The silver current fluctuation was measured using the Differential Pulse Voltammetry (DPV) method. When the concentration of GPC3 was between 1.0 and 70.0 μg/mL, the linear equation was Y=0.2822X +22.6428 (the response current is Y, and the GPC3 concentration is X) with the correlation coefficient of 0.9956, and the lowest detection line was 480 ng/mL. Furthermore, the electrochemical aptasensor demonstrated high specificity and stability.

Development of an electrochemical genosensor for quantitative determination of miR-200a based on the current response of ferrocene-functionalized graphene oxide nanosheets

The present study describes the construction of a sensitive electrochemical genosensor for detection of miR-200a using ferrocene-functionalized graphene oxide nanosheets (Fc-GO) as an electroactive label. For this purpose, a glassy carbon electrode (GCE) was modified by amino-functionalized CuO nanoparticles decorated on MnO2 nanorods (NH2-CuONPs-MnO2NRs). The process of the genosensor construction is confirmed by electrochemical impedance spectroscopy (EIS). A sensing mechanism has been proposed based on the π-stacking interaction between Fc-GO nanosheets and the aromatic bases of DNA. The basis of the assay is based on the interaction of the electroactive label of Fc-GO nanosheets with ss-DNA in the absence of the target and its release after hybridization of the ss-DNA with the target, followed by a severe decrease in the current response. Using the genosensor, miR-200a can be measured in the concentration range of 1.0 fM to 0.1 µM and with a detection limit of 0.29 fM using the differential pulse voltammetry method. Depending on the response of the genosensor, a single-base mismatch as well as a non-complementary-one can be detected from the target sequence. Furthermore, the genosensor is capable of measuring miR-200a in a real sample.

Electrochemical sensing of aclidinium bromide with metal ion-assisted molecularly imprinted films

This study explains the fabrication of the highly sensitive electrochemical sensor based on a metal ion-assisted molecularly imprinted polymer (MIP) for the determination of aclidinium bromide (ACL) for the first time. ACL is a relatively new drug in the group of long-acting muscarinic receptor antagonists and has an important place in chronic obstructive pulmonary disease (COPD) treatment. In this work, the MIP-based electrochemical sensor was designed by photopolymerization on the glassy carbon electrode (GCE) surface. The characterization of the electrode performance was evaluated with electrochemical analyses (cyclic voltammetry and electrochemical impedance spectroscopy). In contrast, chemical and morphological analyses were studied by using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). It was successfully applied for ACL determination in standard solution, serum sample, and capsule dosage form with high sensitivity and accuracy using differential pulse voltammetry method meanwhile utilizing the 5 mM solution of [Fe(CN)6]3−/4– as the redox probe. The LOD values for the standard solution and serum sample were found as 2.73 × 10−16 M and 1.76 × 10−16 M, respectively, in the linear range of 1 × 10−15 M and 1 × 10−14 M. Additionally, interference studies and imprinting factor calculations were performed with common interfering agents and using oxitropium bromide, ipratropium bromide, glycopyrronium bromide, and tiotropium bromide to demonstrate the selectivity of the sensor. Finally, the non-imprinted polymer (NIP)-based sensor confirmed the performance of the MIP sensor. To the best of our knowledge, this study is the first one that reports the electrochemical determination of ACL.

A novel comparative study for electrochemical urea biosensor design: Effect of different ferrite nanoparticles (MFe2O4, M: Cu, Co, Ni, Zn) in urease immobilized composite system

A new enzymatic electrochemical biosensor has been developed with the PANI/Nafion composite system containing ferrite nanoparticles with four different transition metals. The ferrite nanoparticles containing copper, cobalt, nickel, and zinc metals were synthesized by the co-precipitation method and their surfaces were modified with tetraethoxysilane and (3-aminopropyl) triethoxysilane to obtain –NH2 function in order to develop the purposed sensing system. The modified and unmodified ferrite nanoparticles were characterized by physically, chemically, and morphologically. Ferrite nanoparticles with suitable for enzyme immobilization were integrated on the GCE surface and covered with PANI/Nafion. According toelectrochemical measurements, it was determined that copper ferrite nanoparticles, which have the lowest bandgap value, significantly increased the biosensor performance. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to monitor biosensor production and evaluate its performance. A detection limit of 0.17 µM and a wide linear range of 0.5–45.0 µM were obtained for the urea detection with the DPV method with the sensing system (Nf/PANI/CuF/Urs). The biosensor has been successfully applied to soil and milk samples with high accuracy. In addition, it has been determined that the proposed method has good reproducibility, selectivity, and stability.

Sensitive detection of citric acid in real samples based on Nafion/ZnO–CuO nanocomposites modified glassy carbon electrode by electrochemical approach

In this approach, the citric acid (CA) in fruit juices was measured in enzyme-free buffer medium using a GCE (glassy carbon electrode) modified with ZnO/CuO nanocomposites (ZnO/CuO NCs) by DPV (differential pulse voltammetry) and CV (cyclic voltammetry) electrochemical methods respectively. The prepared ZnO/CuO NCs are characterized in detail with XRD (X-ray Diffraction), XPS (X-ray photoelectron spectroscopy), FTIR (Fourier-transform infrared spectroscopy), UV–vis. (Ultraviolet visible spectroscopy), FESEM (Field emission scanning electron microscopy) and EDS (Energy dispersive X-ray spectroscopy) analyses. Both DPV and CV, these techniques were applied with ZnO/CuO NCs/Nafion/GCE to analyze CA in the commercial and natural fruit juices. The current data obtained from electrochemical analysis of CA was plotted against the corresponding concentration of CA and found to distribute on the straight-line in the concentration range of 0.15–1.05 mM of CA, which labeled as a linear dynamic range (LDR) for CA detection. The sensor analytical parameters were calculated by considering the active surface area of GCE (0.0316 cm2) of fabricated electrode over the slope of LDR in both cases (CV and DPV). It was found as 0.4358 μAμM−1cm−2 for DPV and 0.4357 μAμM−1cm−2 for CV respectively. Similarly, the lower limits of detection (DL) applying signal/noise (S/N) ratio 3 are also identical as 21.78 ± 1.09 μM for both electrochemical approaches. The sensor parameters (reproducibility, long-time stability in analyzing and response time) were obtained with good and satisfactory results. Besides this, the proposed sensor was performed trustfully in an analysis of the fruit samples. In this consequence, this electrochemical method with binary mixed metal oxide as sensing substrate to develop a portable sensor might be efficient in the sensor technology.

A sensitive and rapid determination of zinc ion (Zn2+) using electrochemical sensor based on f-MWCNTs/CS/PB/AuE in drinking water

An electrochemical method for detecting the presence of zinc (Zn2+) ions in drinking water was developed using functionalized multi-walled carbon nanotubes (f-MWCNTs) and chitosan (CS). Numerous cylinder-shaped graphene molecules make up f-MWCNTs, which have a high mechanical and electrical conductivity. CS benefits from nanomaterials include biocompatibility, biodegradability, and low toxicity, which are excellent in capacity absorption of metal ions. Dangerous levels of metal ions such as zinc are currently present in drinking water as a result of human and natural activity. Zinc toxicity is associated with a variety of disorders, including Alzheimer’s, Parkinson's, diabetes, and cancer. This study incorporated f-MWCNTs and CS with Prussian blue (PB) immobilised on a gold electrode (AuE). Several parameters, including as buffers, pH, scan rate, redox indicator, accumulation time, and volume, were optimised using the cyclic voltammetry (CV) method. According to the CV method, the optimal parameters were phosphate buffered saline (0.1 M, pH 2), 5 mM Prussian blue, 200 mVs-1 scan rate, and 5 s accumulation time. Under ideal circumstances, the differential pulse voltammetry (DPV) method was used to determine the Zn2+ ions concentration range of 0.2–7.0 ppm. The limit of detection (LOD) was 2.60 × 10–7 mol L-1 with a correlation coefficient of R2 = 0.9777. The recovery rate of the developed sensor (f-MWCNTs/CS/PB/AuE) ranged from 95.78 to 98.96%. The developed sensor showed a variety of advantages for detecting Zn2+ in drinking water, including a quick setup process, quick detection, high sensitivity, and mobility. This study developed the essential sensor for monitoring Zn2+ levels in drinking water in the future.

Synthesis of novel nanostructured copper tungstate/GCE electrochemical system in deep eutectic solvent medium for simultaneous detection of dopamine and paracetamol

• DES solvent consist of 1: 1 M ratio of choline chloride and ethylene glycol is used as a ecofriendly solvent. • A nanostructure of CuWO 4 has been synthesized. • The prepared material is used effectively for the electrochemical sensing of dopamine and paracetamol with a detection limit of 24 nM and 14 nM in a linear range 0.6 × 10 −8 M–26 × 10 −6 M for DA and PAR, respectively. • The better current sensitivity of 9.4833 and 25.11µA µM −1 cm −2 for DA and PAR was found. Deep Eutectic Solvent (DES) based systems are considered as eco-friendly approach, it can be applied to prepare copper tungstate nanorods with nanometer-size ranges. The synthesis of a novel nanostructured CuWO 4 /GCE electrochemical system in Deep Eutectic Solvent medium is described in the present study. Detailed characterization studies have been carried out to observe the surface morphology, crystallinity, and elemental composition of the nanocrystalline CuWO 4 . Cyclic voltammetry (CV) and electrochemical impedance studies (EIS) provide electrochemical and interfacial electron transfer characteristics of the CuWO 4 /GCE system in 0.1 M phosphate buffer medium. The synthesized CuWO 4 /GCE electrode is exploited for both individual and simultaneous electrochemical detection of biologically important molecules dopamine (DA) and paracetamol (PAR) in the physiological pH range. The proposed system exhibits an enhanced current response towards electrochemical oxidation of DA and PAR and it can be extended to use further for the electrochemical determination in biological as well as pharmaceutical formulations in nanomolar concentration ranges. Differential pulse voltammetry method was applied to determine a wider linear concentration in the range of 6.0 × 10 −7 –26 × 10 −5 M and 6.0 × 10 −7 –30 × 10 −5 M, under the optimized experimental conditions, for DA and PAR, respectively. Because of enhanment in electrocatalytic properties, excellent sensitivity, and long-term stability, the prepared CuWO 4 /GCE sensor can be considered a novel promising system for sensing dopamine and paracetamol.

Silk Derived Fe/N-Doping Porous Carbon Nanosheets for Chloramphenicol Electrochemical Detection

Background: The use of modified electrochemical sensors is essential for the detection of antibiotic drug abuse. The main objective of this article is to develop a silk-derived carbon material for the modification of pyrolytic graphite electrodes (PGE) for the sensitive detection of chloramphenicol (CAP). Methods: We proposed a pyrolysis synthesis of porous carbon nanosheets (Fe-Silk PNC) using silk as a precursor. Properties of carbon nanosheets had been improved by the Fe-Nx atoms doping, which was attributed to the β-sheet structures and amino-group-rich chemical structures of silk fibroin, and this material has been used to modify the pyrolytic graphite electrode (PGE) for the electrochemical determination of CAP. Scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR) were used to determine the morphology and properties of Fe-Silk PNC surface. In the electrochemical determination, cyclic voltammetry (CV) showed a superior current response while bare electrode performed an inferior result. In addition, different scan rate, pH, accumulation time and accumulation potential were carefully optimized, which proved that this material is appropriate for CAP detection. Finally, differential pulse voltammetry (DPV) method was used for quantitative measurements. Result: In this study, DPV determination of CAP showed the linear relationship with increasing concentration ranged from 1 to 200 μM, and the low detection limit was 0.57 μM (S/N = 3). SEM and FT-IR results further demonstrated the N-doped carbon nanomaterials were successfully synthesized. With excellent sensing performance achieved, the practicability of the sensor has been evaluated to detect CAP in chicken, shrimps and fish. Conclusion: In summary, a silk derived biomass porous carbon nanomaterial Fe-Silk PNC was simply fabricated and used as a novel electrode material. This kind of novel Fe-Silk PNC modified electrode exhibited excellent sensitivity, anti-interference ability, repeatability, wide linear rang, and was successfully used for determination of CAP in real samples. Therefore, the biomass derived nanomaterial is expected to be used in new sensing materials.