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Electrochemical sensors consisting of screen-printed electrodes (SPEs) are recurrent devices in the recent literature for applications in different fields of interest and contribute to the expanding electroanalytical chemistry field. This is due to inherent characteristics that can be better (or only) achieved with the use of SPEs, including miniaturization, cost reduction, lower sample consumption, compatibility with portable equipment, and disposability. SPEs are also quite versatile; they can be manufactured using different formulations of conductive inks and substrates, and are of varied designs. Naturally, the analytical performance of SPEs is directly affected by the quality of the material used for printing and modifying the electrodes. In this sense, the most varied carbon nanomaterials have been explored for the preparation and modification of SPEs, providing devices with an enhanced electrochemical response and greater sensitivity, in addition to functionalized surfaces that can immobilize biological agents for the manufacture of biosensors. Considering the relevance and timeliness of the topic, this review aimed to provide an overview of the current scenario of the use of carbonaceous nanomaterials in the context of making electrochemical SPE sensors, from which different approaches will be presented, exploring materials traditionally investigated in electrochemistry, such as graphene, carbon nanotubes, carbon black, and those more recently investigated for this (carbon quantum dots, graphitic carbon nitride, and biochar). Perspectives on the use and expansion of these devices are also considered. [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]

A novel electrochemical method for determination of losartan using a glassy carbon electrode modified with carbon black nanoparticles immobilized within a crosslinked chitosan film is proposed. The electrochemical behavior of losartan was investigated using cyclic voltammetry, which presented an irreversible oxidation peak at a potential of + 1.28 V vs. Ag/AgCl (3.0 mol L−1 KCl). The electroactivity of losartan on the modified electrode was significantly improved in terms of peak potential and peak current intensity comparatively to bare working electrode. Using square-wave voltammetry technique under optimized conditions, the modified electrode showed a linear response in the concentration range of 4.97 to 47.6 μmol L−1 with a limit of detection of 0.479 μmol L−1. The developed electrochemical method was successfully applied for the determination of losartan in pharmaceutical formulation samples, with results consistent with those obtained by a comparative UV-Vis spectrophotometric method at 95% confidence level. In addition, losartan quantification was also achieved at synthetic biological fluid samples. [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]

Carbon Black (CB) has acquired a prominent position as a carbon nanomaterial for the development of electrochemical sensors and biosensors due to its low price and extraordinary electrochemical and physical properties. These properties are highly dependent on the surface chemistry and thus, the effect of functionalization has been widely studied for different applications. Meanwhile, the influence of CB functionalization over its properties for electroanalytical applications is still being poorly explored. In this study, we describe the use of chemically functionalized CB Vulcan XC 72R for the development of sensitive electrochemical biosensors. The chemical pre-treatment increased the material wettability by raising the concentration of surface oxygenated functional groups verified from elemental analysis and FTIR measurements. In addition, it was observed an enhancement of almost 100-fold on the electron transfer rate constant ( k 0 ) related to unfunctionalized CB, confirming a remarkable improvement of the electrocatalytic properties. Finally, we constructed a Tyrosinase (Tyr) biosensor based on functionalized CB and dihexadecylphosphate (DHP) for the determination of catechol in water samples. The resulting device displayed an excellent stability with a limit of detection of 8.7 × 10 −8  mol L −1 and a sensitivity of 539 mA mol −1  L. Our results demonstrate that functionalized CB provides an excellent platform for biosensors development. [ABSTRACT FROM AUTHOR]

New progress in the application of voltammetry of immobilized microparticles (VIM) technique in electroanalytical chemistry is reported in this work through the determination of hydroquinone in dermatologic cream samples. The designed electrode was based on a glassy carbon electrode modified with a crosslinked chitosan film containing immobilized carbon black nanoparticles and hydroquinone standards or sample. The electrochemical features of immobilized hydroquinone were explored, which a fast electron transfer kinetic was verified from the perfect reversible redox behavior of this molecule. All the experimental conditions were optimized, including supporting electrolyte condition (composition, pH, and ionic strength) and technical parameters of differential pulse voltammetry (DPV). Under the optimized experimental conditions, the analytical curve was linear by a wide concentration range from 2.7 to 43 ng, with detection and quantification limits of 0.045 and 0.15 ng, respectively. Two commercial dermatologic cream samples were successfully immobilized and analyzed using the proposed VIM procedure, and the results were similar to those recorded by a spectrophotometric comparative procedure. Our set of results represents a unique and exciting advance in the scenario of electroanalytical chemistry for future applications. [ABSTRACT FROM AUTHOR]

Carbon black (CB) is a nanostructured material widely used in several industrial processes. This nanomaterial features a set of remarkable properties including high surface area, high thermal and electrical conductivity, and very low cost. Several studies have explored the applicability of CB in electrochemical fields. Recent data showed that modified electrodes based on CB present fast charge transfer and high electroactive surface area, comparable to carbon nanotubes and graphene. These characteristics make CB a promising candidate for the design of electrochemical sensors and biosensors. In this review, we highlight recent advances in the use of CB as a template for biosensing. As will be seen, we discuss the main biosensing strategies adopted for enzymatic catalysis for several target analytes, such as glucose, hydrogen peroxide, and environmental contaminants. Recent applications of CB on DNA-based biosensors are also described. Finally, future challenges and trends of CB use in bioanalytical chemistry are discussed. [ABSTRACT FROM AUTHOR]

The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate and carbon black (CB) nanoparticles were incorporated within a crosslinked chitosan film over the surface of a glassy carbon electrode, and the obtained architecture explored to the sensitive voltammetric sensing of Allura red colorant in soft drinking powders. The different electrodic surfaces were morphologically and electrochemically characterized. From the modification of glassy carbon electrode with IL and CB, a significantly enhanced voltammetric response was achieved toward the Allura red irreversible oxidation reaction. The type and amount of IL employed in the electrode modification step as well as all the others experimental parameters affecting the sensor response by square-wave adsorptive anodic stripping voltammetry (SWAdASV) were systematically optimized. Under the optimum experimental conditions, the proposed SWAdASV procedure provided a linear analytical curve in the concentration range of 3.98 × 10−8 to 9.09 × 10−7 mol L−1 and a low limit of detection of 9.1 × 10−10 mol L−1 (0.91 nmol L−1). The proposed sensor presented good precision and no matrice effects as shown from repeatability tests, concomitant studies and addition/recovery assays. The developed SWAdASV procedure was applied successfully in the determination of Allura red content in commercial soft drink powder samples, and the results were in close agreement with those obtained using a comparative spectrophotometric method at a confidence level of 95%. Image 1 • Nanostructured sensor based on carbon black nanoparticles and ionic liquid. • Synergism of carbon black and ionic liquid as electrode modifiers. • Electrochemical sensing of allura red at nanomolar levels. • Food analysis by electroanalytical tools. [ABSTRACT FROM AUTHOR]

The outstanding electronic properties of carbon black (CB) and its economic advantages have fueled its application as nanostructured electrode material for the development of new electrochemical sensors and biosensors. CB-based electrochemical sensing devices have been found to exhibit high surface area, fast charge transfer kinetics, and excellent functionalization. In the present work, we set forth a comprehensive review of the recent advances made in the development and application of CB-based electrochemical devices for pharmaceutical and biomedical analyses – from quantitative monitoring of drug formulations to clinical diagnoses - and the underlying challenges and constraints that need to be overcome. We also present a thorough discussion about the strategies and techniques employed in the development of new electrochemical sensing platforms and in the enhancement of their analytical properties and biocompatibility for anchoring active biomolecules, as well as the combination of these sensing devices with other materials aiming at boosting the performance and efficiency of the sensors. • Carbon black as an inexpensive and high-performance electrochemical material. • Last advances on carbon black-modified electrodes for pharmaceutical and biomedical analyses. • Electrochemical sensing and biosensing approaches have been discussed. • Perspectives and challenges on carbon-black based (bio)sensors are highlighted. [ABSTRACT FROM AUTHOR]

A low-cost and disposable microcell was constructed with a screen-printed electrode for the non-enzymatic electrochemical determination of creatinine. The working electrode was modified with carbon black and maintained in contact with paper-adsorbed iron (III) ions. A small sample volume of 3 μL was required for the device operation. Then, iron (III) ions were complexed in the presence of creatinine in a chemical step, followed by an electrochemical reduction of non-complexed metallic ions in excess. Cyclic voltammetry and differential-pulse voltammetry experiments were employed for the electrochemical characterizations and analytical performance evaluation of the microcell. The working electrode modification with carbon black provided a significant increase of analytical signal. The sensor presented a linear response for creatinine concentrations ranging from 0.10 to 6.5 mmol L−1, with a limit of detection of 0.043 mmol L−1. Experiments for creatinine determination in real samples were successful performed through of standard recovery in urine. Image 1 • Creatinine was determinate by a non-enzymatic, low-cost, and disposable microcell. • A small urine sample volume of 3 μL was required for the operation of the device. • The working electrode modification with carbon black provided a significant increase of analytical signal. [ABSTRACT FROM AUTHOR]