Search

A voltammetric sensor comprising a paste electrode made of graphitized thermal carbon black CarboblackC and nanosized zeolite MFI was developed for selective recognition and determination of tryptophan enantiomers. It was found that in determining tryptophan enantiomers, the dependence remains linear at concentrations from 5×10−5 to 1×10−3 M. The detection limits of tryptophan L‐ and D‐enantiomers were calculated to be 4.98×10−7 M and 3.20×10−7 M, while their lower limits of determinable concentrations–1.66×10−6 M and 1.07×10−6 M, respectively. The sensor is more sensitive to D‐tryptophan (ΔEp=20 mV, ipD/ipL=1.58). The developed sensor was shown to successfully determine tryptophan enantiomers in model solutions of pure enantiomers, in a mixture of enantiomers, in biological fluids, and in tablet forms of biologically active additives. It was shown that the suggested sensor made it possible to determine the ratio of L‐ and D‐enantiomers of tryptophan in a mixture with a high probability. [ABSTRACT FROM AUTHOR]

The 3D photoelectrochemical cell was developed with epoxy resin and a working composite electrode produced with a blend of 3D printer commercial conductive filament of polylactic acid biopolymer and carbon black (PLA/CB) mixed with silica/tungsten (VI) oxide (SiO2/WO3) synthesized was used for the determination of imidacloprid in water samples. Imidacloprid is a neonicotinoid pesticide considered potentially neurotoxic, and investigating its presence in aquatic environments is of great importance. The PLA/CB/SiO2/WO3 sensor was morphologically characterized by scanning electron microscopy. Photoelectrochemical performance of the composite sensor was evaluated by chronoamperometry, electrochemical impedance spectroscopy and cyclic voltammetry. In the presence of light (on) using differential pulse voltammetry in borate buffer solution (0.1 mol L−1, pH 7.0), the modified sensor exhibited a linear range of 0.15–93.70 μmol L−1 and with a limit of detection of 0.04 μmol L−1 to determine imidacloprid. The modified sensor did not present interferences for K+ and Fe3+ ions, carbendazim, glyphosate and thiamethoxam pesticides. Furthermore, the recovery in spiked samples successfully determined the presence of imidacloprid pesticide in tap water and natural river surface water. [ABSTRACT FROM AUTHOR]

The additive manufacturing technique through fused deposition modeling (FDM), popularly known as 3D printing, has become a powerful tool for the fabrication of electrochemical sensors, as it allows the development of different device models at a low cost. Thus, this work describes the use of a commercial conductive filament composed of carbon black (CB) dispersed on a polylactic acid (PLA) polymer matrix to construct a disposable electrode for monitoring paracetamol (PAR) in pharmaceutical formulations by differential pulse voltammetry (DPV). Additionally, the sensor was modified with reduced graphene oxide (rGO), evidencing the synergistic effect of carbon nanomaterials with anticipation of the oxidation peak, increase of the analytical response, and favoring of the oxidation‐reduction process on the electrochemical surface. The sensor was further characterized by microscopic and electrochemical techniques. The optimized method by DPV promoted a wide linear working range (10 to 300 μmol L−1), excellent detectability (72.5 nmol L−1), and adequate precision (RSD <3.6 %) and accuracy with recovery percentages of 96 and 102 % for doped samples. Furthermore, the sensor is free from interference with other substances in the pharmaceutical formulation matrices. Finally, the reliability of the results was statistically attested by comparison with those obtained by liquid chromatography. So, the proposed method is accurate for the monitoring of paracetamol in pharmaceutical formulations, highlighting the lower reagent consumption and interferences in the analytical process. [ABSTRACT FROM AUTHOR]

Dopamine (DA) is a crucial neurotransmitter in the central nervous system (CNS) of human and multicellular animal brains. In this paper, we report for the first time the synthesis of carbon black (C)/phosphotungstic acid (PWA) composites by doping PWA on carbon black nanoparticles by impregnation method. The synthesized materials were characterized using high‐resolution scanning electron microscopy (SEM), X‐ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FT‐IR). Glassy carbon electrodes (GCE) modified by C/PWA composites were used to detect dopamine. The electrochemical redox behavior of DA was studied with cyclic voltammetry (CV). Under optimized conditions, DA was detected by differential pulse voltammetry (DPV) and the calibration plot showed linearity (R2=0.9988) over the range of DA concentrations of 10 μM‐600 μM with a detection limit of 0.1 μM. The sensor's capability to detect DA in commercial DA injections in real time has been successfully demonstrated. [ABSTRACT FROM AUTHOR]

Alloying high‐cost Pt with transition metals has been considered as an effective route to synthesize the electrocatalysts with low Pt loading and excellent activity towards oxygen reduction reaction (ORR) under acid solution. The galvanic replacement method, as featured with efficiency and simplicity, is widely reported to produce Pt‐based bimetallic alloys and thereby declare the significance of reductive transition metal precursor on the enhancement of ORR performance. Herein, mix‐phased Cu−Cu2O precursor was applied to prepare carbon black supported highly dispersed PtCu alloy nanoparticles (PtCu/C). The proper Cu−Cu2O ratios can exactly facilitate the generation of small sized PtCu alloy nanoparticles with regulated bimetallic content. Meanwhile, the Cu2O phase is revealed to benefit the electron transfer from Pt to Cu and thus improve the intrinsic activity of Pt active sites. And the metallic Cu can favor the promotion of electrochemical active surface area. Consequently, the as‐prepared PtCu/C behaves impressive ORR activity with half‐wave potential of 0.88 V (vs. RHE) and mass activity of 0.49 A cm−2 mgPt−1 at 0.8 V, which is 9.8 times of commercial Pt/C catalysts. Our work will offer helpful advices for the development and regulation of novel Pt‐based alloy materials towards diverse electrocatalysis. [ABSTRACT FROM AUTHOR]

This work reports the construction of screen‐printed electrode (SPE) modified with carbon black (CB) and magnetic Fe3O4 nanoparticles coated with molecularly imprinted polymer (mag@MIP) based on an alternative low‐cost approach. The proposed device was used for the sensitive and selective voltammetric determination of the antibiotic ciprofloxacin. The results obtained from cyclic voltammetry pointed to the improvement of the SPE response toward the irreversible oxidation of ciprofloxacin after the modification of the electrode surface with CB‐based film and the magnetic preconcentration of mag@MIP containing adsorbed ciprofloxacin molecules. Compared to the non‐molecularly imprinted sensor (mag@NIP), the presence of cavities selective for ciprofloxacin recognition in the mag@MIP nanoparticles accounted for the improvement in analytical signal of the molecularly imprinted sensor. The application of differential pulse voltammetry for ciprofloxacin determination yielded a linear response in the concentration range of 0.5 to 7.0 μmol L−1. The repeatability and interference tests results showed that the proposed electrochemical sensor has good measurement accuracy and selectivity. The proposed device was applied for the voltammetric determination of ciprofloxacin in river water and synthetic urine samples, where recovery rates close to 100 % were recorded for all the samples. The quantification data obtained from the application of the proposed voltammetric method were quite consistent with those of the HPLC reference method. [ABSTRACT FROM AUTHOR]

In this work, we reported a new strategy based on DNA strands hydrolysis in combination with the employment of functionalized carbon black modified screen‐printed electrode (f‐CB/SPE) for guanine detection. Using glass microbeads as a solid substrate of ssDNA probe fixation, and under appropriate conditions of temperature, time, and hydrochloric acid concentration, DNA hydrolysis has been successfully used to release the guanine, allowing its oxidation at f‐CB/SPE using differential pulse voltammetry. The selectivity was successfully tested with a non‐complementary sequence, and a detection limit of 0.7 nM of the target DNA has been reached. [ABSTRACT FROM AUTHOR]

In this work a comparative study of Screen‐Printed Carbon Electrodes (SPCE) – bare and modified by drop casting with carbonaceous nanomaterials (CNMs) as Multi Walled Carbon Nanotubes (MWCNT), Carbon Black and Functionalized Carbon Black for voltammetric determination of 5‐methyl‐6‐nitro‐7‐oxo‐4,7‐dihydro‐1,2,4‐triazolo[1,5‐a]pyrimidinide l‐arginine monohydrate (Triazid) as a potential drug with a broad spectrum of antiviral activity is reported. Bare SPCE and CNMs modified SPCE (SPCE/CNMs) have been characterized morphologically by SEM and electrochemically by cyclic voltammetry/electrochemical impedance spectroscopy with [Fe(CN)6]4−/3− as redox probe. Significant improvement of electrochemical performances is achieved with SPCE/CNMs compared with the bare SPCE. Among SPCE/CNMs studied SPCE modified with MWCNT (SPCE/CNT) is characterized by the best combination of electrochemical properties and electroanalytical performance towards TD. The linear dynamic range is 25–200 mg L−1 (R2=0.9975) with the limit of detection – 2.8 mg L−1 Triazid using SPCE/CNT and Square‐Wave Voltammetry technique. The developed sensor was successfully used for Triazid determination in the Pharmaceutical Substance "TRIAZID". The results achieved with SPCE/CNMs after chemical binding of dissolved oxygen in 0.04 M Britton‐Robinson buffer+0.04 M Na2SO3 (pH 7.2±0.2) are very useful for further development of cost‐effective and time‐consuming pharmaceutical routine assay. [ABSTRACT FROM AUTHOR]

Electrochemical sensors to quantify concentrations of emerging pollutants have attracted great attention from the industry and scientific community. Nanomaterials such as carbon black have been applied in sensors to identify substances that are toxic to the environment and human health due to their excellent electroanalytical properties. The aim of the study was to develop a novel electrochemical sensor for the endocrine disruptor hormone determination. To our knowledge, for the first time the synthesis of material based on carbon black containing immobilized palladium nanoparticles, with the application for the hormone ethinylestradiol, is reported in the literature. The material was synthesized, characterized, and applied to the determination in tap water and human urine of the synthetic hormone 17α‐ethinylestradiol (EE2), which is currently considered an emerging pollutant. The morphology, structure and electrochemical performance of the sensors were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Differential pulse voltammetry (DPV) in sodium phosphate buffer solution at pH 5.0 allowed the generation of a method to quantify the concentration of 17α‐ethinylestradiol in a linear range of 0.5–119.0 μmol L−1, obtaining 81.0 nmol L−1 of calculated limit of detection (LOD). The system was efficient in detecting 17α‐ethinylestradiol in real urine samples and showed no interferences for ascorbic acid, uric acid, progesterone, and dopamine. It is noteworthy that the results obtained showed good recovery values, considering that the urine samples were not previously treated or pre‐concentrated, which suggests the development of an electrochemical sensor that works in situ and in real time to monitor relevant substances in the control clinical and environmental, with the possibility of point‐of‐care analyses. [ABSTRACT FROM AUTHOR]

This paper reports the development of a simple electroanalytical method for imazethapyr (IMT) determination in rice samples based on molecularly imprinted polymer and functionalized carbon black paste electrode (MIP‐fCBPE). Carbon black (CB) was functionalized by the insertion of oxygenated functional groups upon acid treatment with HNO3 and H2SO4. The functionalized carbon black (fCB) presented higher performance for IMT determination than the CB without functionalization. The insertion of molecularly imprinted polyvinylimidazole (MIP‐VN) in the fCBPE promoted a significant increase in the cathodic peak current even at low proportions (7.5 % w/w) due to the specific binding sites for IMT recognition. For IMT determination, DPV parameters were optimized by the Doehlert matrix applying 0.1 V for 60 s as pre‐treatment in acetate buffer solution (pH 3.0) as supporting electrolyte. The proposed method showed low limit of detection (0.03 μmol L−1), a wide linear range (0.10–70.00 μmol L−1), and good precision in terms of repeatability of intraday measures (RSD%=3.6). The method was applied in rice samples after microwave‐assisted extraction of IMT and the accuracy of the method was evaluated by addition/recovery assays (96.3–105.7 %), being statistically attested using HPLC‐DAD as reference technique. [ABSTRACT FROM AUTHOR]

For the first time, acetylcholinesterase (AChE) biosensors based on mixed carbon nanomaterials (electrochemically reduced graphene oxide (ERGO) and carbon black (CB) particles) were described for the determination of antidementia drugs. Changes in the content of underlying layer allowed varying selectivity and sensitivity of the inhibitor determination. Appropriate limits of detection (LOD) varied in the range from 1 pM to 0.1 nM for donepezil, 5 nM–0.1 μM for berberine, 0.1–50 nM for huperzine A and 0.1–300 nM for galantamine. Variation in the inhibition measurement parameters can be used for increasing selectivity of the measurements. [ABSTRACT FROM AUTHOR]

Glyceline, reline, or ethaline deep eutectic solvents and carbon black nanoparticles within a crosslinked chitosan film are investigated as glassy carbon electrode modifiers for the first time. The selected 5 mgmL-1 glyceline modified GCE was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. Simultaneous determination of acetaminophen and diclofenac by differential pulse adsorptive stripping voltammetry (DPAdSV) presented limits of detection of 2.6×10-8 and 5.2× 10-8 molL-1 for acetaminophen and diclofenac, respectively, in pharmaceutical and biological samples. The obtained results were compared with those obtained by HPLC at a confidence level of 95%. [ABSTRACT FROM AUTHOR]

Herein, we demonstrated miniature solid‐contact ion‐selective electrodes (ISEs) using a commercial mesoporous carbon black (MCB) as ion‐to‐electron transducer. MCB is attractive in its high surface area, good conductivity, relative low cost and availability. ISEs for potassium (K+) and nitrate (NO3−) ions were prepared by subsequently coating the sealed glass capillaries (1.5 mm) with MCB and ion‐selective membranes. Addition of MCB substantially stabilized electrode response by providing adequate double‐layer capacitance and lowering resistance by more than 100× compared to the coated‐wire electrodes. The electrodes exhibited near‐Nernstian slopes of 59.6 (K+ ionophore), 57.8 (K+ ion‐exchanger) and −54.8 (NO3− ion‐exchanger) with standard solutions in the range of 10−5 to 10−1 M. Fast response (∼10 s) and reproducible sensitivities were also obtained in a mixed electrolyte containing interfering ions, although with a baseline drift of 2–10 mV/day in the long term. Importantly, the electrodes can be simply stored in air between measurements and used directly without conditioning in solutions. With simple fabrication and free maintenance, these sensors offer a low cost and convenient alternative to bulk ISEs, especially when sample volumes or space are limited. [ABSTRACT FROM AUTHOR]

An electrochemical sensor using glassy carbon electrode modified with carbon black within a poly(allylamine hydrochloride) film is proposed in this work. The novel sensor was characterized by scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry using the redox probe Fe(CN)63−/4−. The sensor was applied for the simultaneous determination of dopamine (DA), paracetamol (PAR), amlodipine (AML), and rosuvastatin (RSV). The quantification of all four analytes was carried out by linear sweep voltammetry and presented a linear concentration range for all analytes from 1.0 to 90 μmol L−1, with limit of detection of 0.55, 1.3, 5.7, and 3.0 μmol L−1 for DA, PAR, AML, and RSV, respectively. This sensor was successfully applied in the simultaneous determination of these analytes in environmental, pharmaceutical, and biological samples. [ABSTRACT FROM AUTHOR]

In this work, a renewable tyrosinase‐based biosensor was developed for the detection of catechol, using a carbon black paste electrode, without any mediator. The effect of pH, type of electrolyte, and amount of tyrosinase enzyme were explored for optimum analytical performance. The best‐performing biosensor in amperometric experiments at potential −0.2 V vs. Ag/AgCl (3 mol L−1 KCl) was obtained using a 0.1 mol L−1 phosphate buffer solution (pH 7.0) as electrolyte. Under optimized conditions, the proposed biosensor had two concentration linear ranges from 5.0×10−9 to 4.8×10−8 and from 4.8×10−8 to 8.5×10−6 mol L−1 and a limit of detection of 1.5×10−9 mol L−1. The apparent Michaelis‐Menten constant (KMMMapp) was calculated by the amperometric method, and the obtained value was 1.2×10−5 mol L−1 whose result was similar when compared with other studies previously. The biosensor was applied in river water samples, and the results were very satisfactory, with recoveries near 100 %. In addition, the response of this biosensor for different compounds, taking into account their molecular structures was investigated and the results obtained showed no interference with the response potential of catechol. The electrochemical biosensor developed in this work can be considered highly advantageous because it does not require the use of a mediator (direct detection) for electrochemical response, and also because it is based on a low‐cost materials that can be used with success to immobilise other enzymes and/or biomolecules. [ABSTRACT FROM AUTHOR]

Towards the development of miniaturised and low‐cost sensors for heavy metals detection in water, herein we describe an electrochemical sensor for the co‐detection of lead and cadmium. The sensor was developed using screen‐printed electrode modified with a composite of poly(propylene imine) dendrimer and carbon black. The electrode was modified by drop casting of the carbon black and electrodeposition of the poly(propylene imine) dendrimer. This modified electrode (sensor) was characterised by cyclic voltammetry and electrochemical impedance spectroscopy, revealing improved electrochemical performances. Square wave anodic stripping voltammetry (SWASV) was used to achieve the simultaneous detection of Pb(II) and Cd(II) at trace level, obtaining satisfactory LOD of 3.6 ppb and 15.3 ppb respectively; and sensitivity of 0.49 μA/ppb and 0.57 μA/ppb in tap water. [ABSTRACT FROM AUTHOR]

The recent trend of using sustainable disinfectants in water treatment sector boosted the employment of chlorine dioxide (ClO2) as green disinfectant. Indeed, this disinfectant is characterised by several attractive features such as the working capability in a wide range of pH and the absence of harmful by‐products. These characteristics confer to chlorine dioxide a prominent position between the disinfectants, thus analytical tools for on‐site detection are needed to customize the water treatment. Herein, we described the development of an innovative and cost‐effective carbon black modified screen‐printed electrode for amperometric quantification of chlorine dioxide in standard solution and in swimming pool water. The carbon black as working electrode nanomodifier allowed for the detection of chlorine dioxide at low applied potential, with linear range of 0.05–20 ppm, and a detection limit of 0.01 ppm. The matrix effect evaluation as well as the recovery study demonstrated the capability of this sensor for a cost‐effective detection of chlorine dioxide in swimming pool water, paving the way for the use of miniaturised electrochemical sensors in water treatment field. [ABSTRACT FROM AUTHOR]

A disposable electrochemical paper‐based analytical device was constructed based on use of sequential analysis with multiplexed working electrodes and applied for the determination of glucose, creatinine, and uric acid. The device was constructed with 16 microfluidic channels, with 16 working electrodes arranged in four set with four components surrounding the sample injection hole. In addition, a commercial multiplexing module was used, which allowed for multiplexing of the 16 working electrodes. This design allowed for radial and homogeneous sample elution to each sensing spot for high throughput analysis. In the multiplexed determinations, distinct electrochemical procedures were employed for each analyte. Furthermore, each working electrode spot was modified to increase the respective analytical signals. For glucose detection, the sensor was based on electron mediation by ferrocenecarboxylic acid over the modified surface with glucose oxidase. The principle for creatinine detection was based on electrochemical reduction of non‐complexed Fe3+ in excess after complex formation between Fe3+ and creatinine in the chemical step. The anodic peak current responses for uric acid detection increased due to working electrode surface modification with carbon black nanoparticles. In the multiplexed analysis, the device provided limits of detection of 0.120 mmol L−1, 0.084 mmol L−1, and 0.012 mmol L−1 for glucose, creatinine, and uric acid, respectively. The developed device was successfully applied in the analyses of real urine samples. [ABSTRACT FROM AUTHOR]

The acetylcholinesterase (AChE) biosensor has been developed for the determination of reversible inhibitors applied in the Alzheimer's disease therapy, i. e., Huperzine A (HupA) and galantamine (Gal). For this purpose, glassy carbon electrode (GCE) was first modified with carbon black (CB) and Co phthalocyanine and then polyelectrolyte complex was self‐assembled on its surface by drop casting of reactants and washing. To extend the stability and improve biosensor performance, it was proposed for the first time to use DNA as polyanion in the complex assembly. The DNA showed higher charge density than conventional polyelectrolytes and stabilized the surface coating by adsorption of higher enzyme amount and prevention of its leaching during the biosensor operation. Complex formation and the influence of structural factors were monitored with surface plasmon resonance. Kinetic study showed mixed inhibition of the enzyme within micro‐ and nanomolar range of inhibitor concentrations. The AChE biosensor showed limit of detection of HupA equal to 0.9 and that of Gal to 70 nM. The sensitivity of drug determination was found to be close or better than that of the AChE biosensors previously reported in the literature. The biosensor was tested on the sample of artificial urine and showed 102 % recovery of the drugs determination. [ABSTRACT FROM AUTHOR]

An electrochemical method was developed for the sensitive determination of chlorogenic acid using a boron doped diamond electrode (BDDE) modified with nano‐carbon black (nano‐CB). The active surface areas were found to be 0.059 and 0.146 cm2 for the unmodified BDDE, and nano‐CB/BDDE, respectively. Compared with a BDDE, the nano‐CB/BDDE exhibited a well‐defined redox couple for chlorogenic acid. In addition, the plot of the peak current response changing from a square root to a linear dependence on scan rate is attributed to the transition from planar diffusion to surface behaviour. The anodic and cathodic peak separations (ΔEp) were 97 mV and 14 mV at BDDE and nano‐CB/BDDE, respectively. The decrease in ΔEp at the proposed electrode indicated that the process of chlorogenic acid was greatly accelerated. Square wave voltammetry (SWV) exhibited a dynamic range in which the current versus the concentration of chlorogenic acid were linear from 2.0×10−8 to 2.0×10−6 M with a LOD of 4.1×10−9 M (based on 3Sb/m). The nano‐CB modified BDDE provided improved electrochemical behavior, high electrocatalytic activity, high sensitivity and good reproducibility. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is an environmental endocrine disrupting chemical, which can lead to various adverse health effects. Aiming to develop effective tools for the detection of BPA, this work reports a low cost and stable film based on casein (CAS) and Carbon Black (CB). The proposed material (CAS‐CB) showed structures of CAS surrounded by CB agglomerates observed by Scanning Electron Microscopy while Fourier Transform Infrared Spectroscopy analysis illustrated characteristic bands of casein. Cyclic Voltammetry (CV) and linear sweep voltammetry (LSV) were used to investigate the electrochemical behavior of BPA using the CAS‐CB. Under optimal conditions, LSV detection presented a limit of detection of 0.25 μmol L−1 in a linear range from 0.49 to 24 μmol L−1. Additionally, the working electrode (GC) modified by the proposed film (CAS‐CB) was applied for BPA sensing in environmental and milk samples. The results showed recoveries between 95.4 to 114 % attesting the efficiency of this new material, which has simplicity in the preparation, high conductivity, and adsorption capability. [ABSTRACT FROM AUTHOR]

For the construction of the sensor, three different carbon black (CB) materials (VULCAN XC72R, BLACK PEARLS 4750 and CB N220) were explored as modifying nanomaterial. Firstly, the electrochemical activity of the each SPE modified was compared by cyclic voltammetry and electrochemical impedance spectroscopy technique, using [Fe(CN)6]3−/4− as redox couple. After demonstrating that electrodes modified with different types of CB were characterized by improved electrochemical performances when compared with bare electrodes, and among them, electrodes modified with CB BP4750 is characterised by slightly better electrochemical properties, this type of electrode was used for the development of the analytical method. By applying SWV technique in 0.2 mol L−1 phosphate buffer (pH 3.0), the obtained analytical curves for ACP and LVF were found linearly from 4.0 to 80.0 μmol L−1 and from 0.90 to 70.0 μmol L−1 with limit of detection of 2.6 μmol L−1 and 0.42 μmol L−1 for ACP and LVF, respectively. Finally, the quantification of these drugs in river water was evaluated using the new here‐proposed sensor by recovery method in spiked samples, obtaining satisfactory recovery values. The results achieved demonstrated that the developed analytical tool is of great analytical interest being easy to use, cost‐effective, miniaturized, and thus suitable for low cost on site analysis. [ABSTRACT FROM AUTHOR]

The antidiabetic drug metformin (MET) is one of a group of emerging pharmaceutical drug contaminants in the wastewater treatment plants. The electrochemical behaviour of MET−Cu(II) complex by differential pulse and square wave voltammetry, in a wide pH range, at a glassy carbon electrode modified with a carbon black dihexadecylphosphate film (CB−DHP/GCE), was investigated. The MET−Cu(II) complex oxidation showed one pH‐dependent process, which leads to the formation of an oxidation product, being oxidized at a lower potential. The electroanalytical MET−Cu(II) complex detection limit, LOD=0.63 μM, and quantification limit, LOQ=2.09 μM, were obtained, and the MET−Cu(II) complex determination in wastewater samples collected from a senior residence effluent, using the CB−DHP/GCE, was achieved. Considering MET toxicity, the electrochemical evaluation of MET−dsDNA interaction, in incubated solutions and using dsDNA‐electrochemical biosensors, following the changes in the oxidation peaks of guanosine and adenosine residues electrochemical currents, was also investigated. The MET−dsDNA interaction mechanism, for shorter times, occurs by the binding of MET molecules in the minor grooves of the dsDNA, and for long times, the stabilization of the MET−dsDNA complex, causing a local distortion and/or unwinding of dsDNA morphology, is described. However, MET did not promote DNA oxidative damage. [ABSTRACT FROM AUTHOR]

Carbon nanotube, graphene and carbon black, as electrode modifiers, were compared and evaluated for the electrochemical determination of vancomycin. Among them, the best results were obtained at the graphene‐modified electrode. Additions of vancomycin using square wave voltammetry at the graphene‐modified electrode showed a linear range from 0.70 μM to 50 μM and a detection limit of 0.20 μM was obtained. To control the correct dose of vancomycin and reduce its side effects, its accurate determination in blood plasma is very important. Therefore, the method was applied for the vancomycin determination in spiked human plasma samples and satisfactory recoveries were observed. The developed method exhibited fast analysis, high sensitivity, good repeatability and freedom from other interfering species. [ABSTRACT FROM AUTHOR]

Highly dispersive Au nanoparticles on carbon black (Au NPs/CB) were synthesized in situ with co‐present two different reducing agents of NaBH4 at various concentrations and citrate at a constant concentration of 3 mM. The average diameters of Au NPs on carbon support were in the range from 5.8 (±2.4) to 2.0 (±0.4) nm, with 50 particles quantified. Electrocatalytic activities of as‐prepared Au NPs/CB were explored for oxygen reduction reaction (ORR) in basic solution with rotating disk electrode (RDE) and rotating ring‐disk electrode (RRDE) voltammetry. In results, the Au NPs/CB synthesized with 0.2 mM NaBH4 (2.0 nm of Au NPs diameter) represented the highest ORR catalytic activity with electron transfer number of 3.9 and mass activity of 0.25 mA cm−2 μg−1as well as a perfect resistance to methanol contamination. Especially, the half‐wave potential of ORR curve which related to the kinetics of oxygen reduction was more positive compared with previously reported Au‐based ORR catalysts. In addition, the Au NPs/CB prepared with 0.2 mM NaBH4 was also examined as a CO2 reduction catalyst in KHCO3 with KCl solution with scanning electrochemical microscopy (SECM). CO2 was reduced to CO selectively without hydrogen evolution at Au NPs/CB substrate electrode, which was directly monitored with an electrochemical CO microsensor as a tip electrode in SECM. In addition, we have identified the products of CO2 reduction through gas chromatography (GC)‐mass spectrometry (MS), flame ionization detector (FID), and thermal conductivity detector (TCD). [ABSTRACT FROM AUTHOR]

The paper reports the development of a new sensor based on Printex L6 (CPL6) carbon black modified with copper oxides (CuO/Cu2O) nanoparticles and its application towards the determination of Propylparaben (PP). In fact, it is the first report of its kind in the literature. The sensor was produced through the dispersion of CPL6 in dimethylformamide on glassy carbon electrode surface followed by CuO/Cu2O electrodeposition. The conditions of electrodeposition investigated included time and solution concentration of Cu (II). Morphological, structural and electrochemical characterizations of the sensor were performed. Under optimal conditions, wide linear range (1.0 to 35.0 μmol L−1) was obtained in the detection of PP. The detection limit obtained was 0.46 μmol L−1 (S/N=3). The CuO/Cu2O‐CPL6/GCE sensor was found to be as sensitive as the high performance liquid chromatography in the determination of PP in both cosmetic and river water samples, in addition to being reproducible and stable. [ABSTRACT FROM AUTHOR]

Abstract: Detection of traces from pharmaceutical drugs such as antibiotics in drinking water and foodstuff is essential for guaranteeing human health in some environments, and this has to be done with low cost technologies to be widely deployed in public services and industry. In this paper, we describe an ultralow cost (

Abstract: Synthesis of nanomaterials using cheap and highly efficient material is an important aspect of nanotechnology. In this present work, we have used the carbon black (CB) as a highly conductive and inexpensive carbonaceous material for the fabrication of the electrochemical sensor. However, the poor dispersion in water obstructs the usage of CB in electrochemical sensor and biosensor applications. Hence, the CB was functionalized by simple reflux method and the functionalized CB (f‐CB) nanospheres hybrids with hydrothermally synthesized MoS2 nanoclusters by simple ultrasonication process. In addition, the various suitable spectrometric techniques used to probe the surface morphology and chemical modification of the prepared materials. The prepared MoS2 and f‐CB nanohybrids (f‐CB/MoS2) applied for the electrocatalytic reduction of toxic chloramphenicol (CAP). Fascinatingly, the f‐CB/MoS2 modified electrode showed a competitive electrocatalytic performance comparing with other modified electrodes. At the optimized condition, the sensor exhibited the LOD about 0.002 μM, wider linear range 0.015 to 1370 μM with the sensitivity of 3400 μA μM−1 cm−2 for the determination of CAP. Moreover, the practical viability of the sensor was exploited in milk powder and honey samples. [ABSTRACT FROM AUTHOR]

Electrochemical sensor has been proposed on the base of glassy carbon electrode (GCE) modified with carbon black (CB) and pillar[5]arene (P[5]A). The characteristics of the peak currents were found to be sensitive to the incubation of the sensor in organic acid and DNA solution. The detection of n×(10−8-10−5) M of organic acid and down to (1-5)×10−18 g of DNA was attributed to the effect of the analytes on the aggregation and relative stability of oxidized and reduced forms of P[5]A. No signal interference with the alkali and alkali-earth metal ions was found. The electrochemical sensor was tested in the detection of specific DNA interactions, i.e. reactive oxygen species damage and intercalating pharmaceuticals detection. [ABSTRACT FROM AUTHOR]

In this work, a simple and highly selective voltammetric method was developed for the simultaneous determination of paracetamol (PCT) and codeine (COD) in pharmaceuticals and human body fluids employing a glassy carbon electrode modified with carbon black (CB) and nickel oxide nanoparticles (NiONPs) within a dihexadecylphosphate (DHP) film. Using square-wave voltammetry (SWV), a separation of ca. 550 mV between the oxidation peak potentials of PCT and COD was obtained. The simultaneous determination of PCT and COD presented a linear concentration range from 3.0 to 47.8 µmol L−1 for PCT and from 0.83 to 38.3 µmol L−1 for COD. [ABSTRACT FROM AUTHOR]

In this work a comparative study using Screen-Printed Electrodes (SPEs) modified by drop casting with Carbon Black, Single Walled Carbon NanotubesCOOH, Graphene Oxide, and reduced Graphene Oxide is reported. The carbon nanomaterials employed were characterized by X-ray photoelectron and Raman spectroscopy, while the modified SPEs have been morphologically and electrochemically characterized. Nanoengineered SPEs have been tested with ferricyanide, NADH, ascorbic acid and cysteine. We observed valuable electroanalytical performances of Carbon Black with the advantage to be i) cost-effective ii) suitable to obtain stable and homogenous dispersion and iii) mass-producible following a well established route. [ABSTRACT FROM AUTHOR]

An 'abiotic' biofuel cell composed of catalytic electrodes modified with inorganic nanoparticles (NPs) deposited on carbon black (CB) was used to activate a wireless information transmission system. The cathode and anode were made of carbon paper modified with Pt-NPs/CB and buckypaper modified with Au80Pt20-NPs/CB, respectively. The cathode/anode pair was implanted in orange pulp extracting power from its content (glucose and fructose in the juice). The open circuit voltage, Voc, short circuit current density, jsc, and maximum power produced by the biofuel cell, Pmax, were found as 0.36 V, 1.3 mA cm−2 and 182 µW, respectively. The voltage produced by the biofuel cell was amplified with an energy harvesting circuit and applied to a wireless transmitter. The present study continues the research line where different implantable biofuel cells are used for activation of electronic devices. [ABSTRACT FROM AUTHOR]

An 'abiotic' biofuel cell composed of catalytic electrodes modified with inorganic nanostructured species was used to activate a pacemaker. The catalytic nanoparticles of various compositions, Au xPt y, deposited on carbon black (CB) were prepared and extensively characterized to select the species with selectivity for glucose oxidation and oxygen reduction. Then two kinds of 3D-electrode materials with different morphology, buckypaper composed of carbon nanotubes (ca. 50 nm diameter) and carbon paper made of carbon fibers (ca. 7 µm diameter), were used in a combination with different catalytic species. Finally, Au/CB nanospecies deposited on buckypaper were selected for catalyzing glucose oxidation (composing the biofuel cell anode) and Au60Pt40/CB species deposited on carbon paper were selected for catalyzing oxygen reduction (composing the biofuel cell cathode). The catalytic electrodes were characterized by cyclic voltammetry in an aqueous buffer solution and the polarization function for the biofuel cell was studied in a human serum solution. The open circuit voltage, Voc, short circuit current density, jsc, and maximum power produced by the biofuel cell, Pma x, were found as 0.35 V, 0.65 mA cm−2 and 104 µW, respectively (in human serum at 5.4 mM glucose). The biofuel cell produced the steady state open circuit voltage over 10 hours with its slow decrease over 50 hours originating from the glucose depletion and slow mass-transport within the 3D-electrode. The voltage produced by the biofuel cell was amplified with an energy harvesting circuit and applied to a pacemaker resulting in its proper operation. The present study continues the research line where different implantable (enzyme-based or abiotic) biofuel cells are used for the activation of biomedical electronic devices, e.g., pacemakers. [ABSTRACT FROM AUTHOR]

Both screen-printed electrodes modified with a dispersion of carbon black (CB) and solid paste electrodes prepared using a nanostructured CB were developed and characterized. Indeed, increasing the peak currents and/or their shifting to negative potentials were observed, exhibiting efficient electrocatalytic activity towards nitrite oxidation with high sensitivity and low detection limit. Solid carbon paste electrodes (SCPEs) and solid carbon black paste electrodes (SCBPEs) were challenged in amperometric mode with nitrite since detection limit reached is 65 and 5 nM respectively. Nitrate was first reduced to nitrite in reductor column, then detected on SCBPEs. Nitrate and nitrite were determined in real samples. [ABSTRACT FROM AUTHOR]