Electroanalytical Applications Research Articles

Optimizing laser-induced graphene oxide electrodes for electroanalytical applications using response surface methodology

Optimizing laser-induced graphene oxide electrodes for electroanalytical applications using response surface methodology

Electroanalysis of Statin Drugs: A Review on the Electrochemical Sensor Architectures Ranging from Classical to Modern Systems.

An overview of the latest advances in the design of electrochemical sensor architectures dedicated to the determination of drugs from the statin class is presented in this review. Statins are drugs widely consumed for cholesterol control, and their determination in different matrices through the application of electroanalysis is growing considering advantages such as operational simplicity, lower cost and ease of sample preparation. Within the context of statins, electrochemical sensor architectures can be subdivided into conventional/classical electrodes such as glassy carbon electrodes, carbon paste electrodes, pencil graphite electrodes, boron-doped diamond electrodes and metallic electrodes, and more modern electrode systems, including the screen-printed electrodes and 3D-printed electrodes. Thus, different aspects related to the preparation of these electrochemical sensors and analytical performance are presented, also reflecting advances in terms of designs of new architectures and possible improvements not previously reviewed. Analyzed samples, advantages and disadvantages of different implemented sensor's modification strategies and perspectives for the electroanalysis of statins are also included throughout the work.

The Promise of Carbon Nano‐Onions: Preparation, Characterization and Their Application in Electrochemical Sensing

AbstractCarbon nano‐onions (CNOs) promise to improve the range of applications of carbon materials for electroanalytical applications. In this review, we explore the synthesis, characterization, and electrochemical applications of CNOs. CNO‐based sensors present impressive features, including low detection limits in the femtogram per milliliter range, a broad linear detection range spanning up to 7 orders of magnitude, exceptional selectivity, reproducibility, and stability. Synthetic methods and characterization techniques for CNOs were thoroughly examined, shedding light on their pivotal role in biosensing technologies. Comparative analyses with other carbon materials underscore CNOs′ competitive performance, either surpassing or matching many counterparts. Despite their relatively recent integration in biosensing applications, CNOs exhibit comparable or superior results concerning other carbon‐based materials. Indeed, the incorporation of CNOs into hybrid nanocomposites has shown promising outcomes, indicating a synergistic potential for future advancements in biosensing technologies. Our review provides a broad approach to the application of CNOs to the field, with emphasis on breakthroughs of the last 5 years.

Quo Vadis, Elimination Voltammetry?

The article presents an open personal approach to the future of elimination voltammetry with linear scan (EVLS) in the context of the expected development and research of new materials and new technologies. With this development, the application capability of EVLS will be expanded, the basis of which is a mathematical apparatus that allows some current components to be eliminated from the overall voltammetric record, while others to be preserved. Although EVLS played a provisional and unquestionable role in electroanalytical applications, where it helped to obtain lower limits of detection (LOD) values of various organic and inorganic substances and to reveal electrode processes hidden in voltammetric signals, its further development indicates promising use in other research areas as well. The aim of the communication is a more precise but also more general definition of the elimination method, its specific paradigms, prospects and goals for the future.

Advancement of Graphite-Clay Composite Electrodes via Different Compositions to Improve the Synergetic Matrix Effect Towards General Electroanalytical and Energy Storage Applications

Modern electrode technology trends for enhancing multifunctional electrodes, prioritizing energy storage and electroanalytical prospects. This study anticipates fabricating electrodes by incorporating cement and colloidal graphite, to improve the performance via synergetic interactions of the composite matrix. Graphite-montmorillonite-cement ternary composite electrode (GMMTCeCE) and graphite-colloidal graphite-montmorillonite-cement quaternary composite electrode (GCGMMTCeCE) are fabricated, as two types of electrodes. GMMTCeCE reflects the lowest peak-to-peak separation in Ce3+/Ce4+ (0.098 V), greater sensitivity towards [Fe(CN)6]4- (2.68 A·m·mol-1) and [Fe(CN)6]3- (2.64 A·m·mol-1), showing comparatively better performance in analyte detection than GCGMMTCeCE. Multilayered polyaniline (PANI) nanofibers network, which is unique in GMMTCeCE electropolymerization, accounts for very low serial (0.38 Ω) and charge transfer (0.59 Ω) resistances, while densely packed nanofibers of PANI in GCGMMTCeCE is responsible for the lowest ohmic resistance (1.31 Ω). Supercapacitor device fabricated by PANI-GMMTCeCE, achieved higher capacitance (1,002 F·g-1 at 5 mV·s-1) and showed greater cyclic stability, in contrast to relatively lower specific capacitance (685 F·g-1 at 5 mV·s-1) attained by PANI-GCGMMTCeCE, demonstrates the superiority of the supercapacitor of GMMTCeCE over GCGMMTCeCE for energy-storage purposes. Therefore, GMMTCeCE outperformed GCGMMTCeCE in electroanalysis and energy storage, confirming better synergetic interactions of the ternary composite matrix over the quaternary one. Besides, further improvements in graphite-clay composite matrix properties facilitate the advancement of electrochemical sensors and supercapacitor devices.

Coffee Biomass-Based Carbon Material for the Electrochemical Determination of Antidepressant in Synthetic Urine

Escitalopram (ESC) is commonly prescribed as an antidepressant to enhance serotonin levels in the brain, effectively addressing conditions such as depression and anxiety. The COVID-19 pandemic, along with ongoing mental health crises, has exacerbated the prevalence of these disorders, largely due to factors such as social isolation, fear of the virus, and financial difficulties. This study presents the enhancement of a glassy carbon electrode (GC) through the incorporation of hydrochar (HDC) derived from spent coffee grounds and copper nanoparticles (CuNPs) for the detection of ESC in synthetic urine. Characterization of the nanocomposite was conducted using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and cyclic voltammetry (CV). The analytical parameters were systematically optimized, and a sensing platform was utilized for the quantification of ESC via square-wave voltammetry (SWV). The established linear range was found to be between 1.0 µmol L−1 and 50.0 µmol L−1, with a limit of detection (LOD) of 0.23 µmol L−1. Finally, an electrochemical sensor was employed to measure ESC levels in synthetic urine, yielding recovery rates ranging from 91.7% to 94.3%. Consequently, the HDC-CuNPs composite emerged as a promising, sustainable, and cost-effective alternative for electroanalytical applications.

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.

Enhanced electrochemical performance of 3D-printed electrodes via blue-laser irradiation and (electro)chemical treatment

Extrusion-based 3D printing technologies, especially fused filament fabrication (FFF) using conductive filaments, have significantly advanced in electroanalytical applications by enabling the fabrication of electrochemical sensors. Nonetheless, 3D-printed electrodes produced from commercially available conductive filaments (e.g., polylactic acid containing carbon black - CB/PLA) often contain a low amount of conductive material (∼20 % wt. carbon black), requiring surface activation protocols to enhance their electrochemical performance. In this study, we investigated the combination of blue-laser (BL) irradiation and (electro)chemical treatment (EC) to improve the performance of 3D-printed electrodes. For this purpose, 3D-printed CB/PLA electrodes were subject to blue laser activation (laser power = 280 mW and scan rate = 30 mm s-1) followed by an electrochemical procedure in 0.5 mol L-1 NaOH solution (application of +1.4 V and – 1.0 V both for 200 s). After the combined treatment, a considerable improvement in the voltammetric profile response (Ipa/Ipc = 1.00 and ΔEp = 136 mV) was achieved using 1 mmol L-1 [Fe(CN)6]3-/4- (equimolar concentration) as the redox probe when compared to polished electrodes (Ipa/Ipc = 0.85 and ΔEp = 690 mV). Scanning electron microscopy, infrared spectroscopy data and X-ray photoelectron spectroscopy showed that the combined treatment promotes the remotion of insulating PLA material, exposing more conductive sites and functional groups. Moreover, electrochemical impedance spectroscopy results showed low resistance to charge transfer and capacitance double-layer measurements revealed an increase in the electroactive area after surface activation. As proof of concept, emerging contaminants such as hydroxychloroquine (HCQ) and paracetamol (PRT) were determined in tap water and pharmaceutical samples using treated 3D-printed CB/PLA electrodes and square-wave voltammetry. Linear ranges of 0.20 - 12.30 µmol L-1 and 1.0–30.0 µmol L-1 with limit of detection values of 0.01 and 0.2 µmol L-1 were obtained for HCQ and PRT, respectively. Appropriate recovery values (90 - 111 %) for the analysis of spiked samples were achieved.

Bionanocomposite materials for electroanalytical applications: current status and future challenges.

Bionanocomposites are materials composed of particles with at least one dimension in the range of 1-100 nm and a constituent of biological origin or biopolymers. They are the subject of current research interest as they provide exciting platforms and act as an interface between materials science, biology, and nanotechnology and find applications in disciplines such as electrochemistry, biomedicine, biosorption, aerospace, tissue engineering and packaging. They have different properties such as high conductivity, thermal stability, electrocatalytic ability, biocompatibility, adsorption ability and biodegradability, which can be tuned by their preparation methods, functionalities and applications. However, depending on the objective or the goal of a research project, specific preparation and characterization of bionanocomposites can be undertaken to understand the behavior and confirm the applicability of a bionanocomposite in a given field. Like in electroanalysis applications, electrode materials should be porous (meso- and macro-porosities), having large specific area (at least having a Brunauer-Emmett-Teller surface of 200 m2 g-1), higher stability over time with acceptable power recovery between 95% and 105%, good electrocatalytic ability, and be a good absorbent and a good conductor of electricity (that is to say, it facilitates the transfer of electrons from the solution to the surface of the electrode and vice versa). The present review focuses on the most used method of preparation of bionanocomposites with the critical aspect and their physicochemical and electrochemical characterization techniques, and finally, the practical situations of application of bionanocomposite materials as modified electrodes for electroanalysis of several groups of analytes and a comparison with non-bionanocomposite electrodes are discussed. The future scope of bionanocomposites in the field of electroanalysis is also addressed in this review. But before that, a general overview of bionanocomposite materials in relation to other types of materials is presented to avoid any misunderstanding.

Selecting optimal carbon inks for fabricating high-performance screen-printed electrodes for diverse electroanalytical applications

Carbon-based screen-printed electrodes (SPEs) are extensively employed in electrochemistry due to their reproducibility, low-cost production, disposability and versatility. It is commonly accepted that batch to batch variations may occur due to variations in the ink formulation or the use of a different ink to print the electrodes. In this paper, three different commercial carbon-based inks (DuPont, Loctite and SunChemical) were used to manufacture SPEs, referred to respectively as Dup-SPE, Loc-SPE and Sun-SPE, using a semi-automated screen-printing technology. This study focuses on evaluating the quality, characteristics and electrochemical performance of the fabricated SPEs. Furthermore, the study aimed to investigate potential correlations between the ink composition and the nature of different target molecules, as well as their electroanalytical responses. Specifically, phenolic compounds and cocaine cutting agents are tested in alkaline conditions, while benzodiazepines and cephalosporine antibiotics are investigated in acidic media using square wave voltammetry (SWV). This aims to extract insights for the proper selection of inks and SPEs in both conditions. Additionally, a scan rate study of cephalosporine antibiotics using linear sweep voltammetry (LSV) is performed confirming the ion-exchange polymer layer on the electrode surface of Loc-SPE, which impact surface and electrochemical properties, leading to drawbacks in alkaline SWV sensing, but strategic benefits in reductive sensing resulting in an enhanced selective detection of specific targets. The insights on ink-specific influences on the surface and electrochemical properties of the SPEs obtained, may be useful for facilitating the electrode selection in diverse electrochemical applications, emphasizing the critical role of ink composition in achieving desired sensing capabilities.

Ag-La(OH)3@Dy2O3 hybrid composite modified laser-induced graphene surface for simultaneous electrochemical detection of bisphenol A and tartrazine

Laser-induced graphene (LIG), created through CO2 laser irradiation of polyimide film (PI) substrates, has emerged as a versatile and promising material in numerous fields. However, despite its potential, a comprehensive exploration of LIG’s surface structure and reactivity remains absent in the literature, which is crucial for advancing its applications in electrochemical and electroanalytical fields. In this study, we developed and examined the interfacial structure and electronic behavior of an Ag-La(OH)3@Dy2O3 hybrid composite-modified LIG system as a model. We employed scanning electrochemical microscopy (SECM) to investigate these properties, extending our analysis to the simultaneous detection of organic pollutants, such as bisphenol A (BPA) and tartrazine (TRZ), in real samples. Compared to previous LIG production techniques, the LIG-modified electrode demonstrated a high electron transfer rate at the interface. The tailored LIG substrate showed excellent electrochemical activity towards electrochemical oxidation and simultaneous electroanalytical applications for BPA and TRZ with low detection limits (BPA: 9.2 nM, TRZ: 0.96 nM) in neutral physiological conditions. As a proof of concept, an extension to the real-time application of simultaneous monitoring of BPA and TRZ in various food samples was successfully demonstrated.

Shungite Paste Electrodes: Basic Characterization and Initial Examples of Applicability in Electroanalysis

This article introduces a new type of carbon paste electrode prepared from black raw shungite. In powdered form, this carbonaceous material was mixed with several nonpolar binders. The resulting shungite pastes were microscopically and electrochemically characterized. Mixtures of several pasting liquids with different contents of shungite powder were tested to select the optimal composition and compared with other types of carbon paste-based electrodes made of graphite and glassy carbon powder. In terms of physical and mechanical properties, shungite paste electrodes (ShPEs) formed a composite mass being like dense pastes from glassy carbon microspheres, having harder consistency than that of traditional graphitic carbon pastes. The respective electrochemical measurements with ShPEs were based on cyclic voltammetry of ferri-/ferro-cyanide redox pairs, allowing us to evaluate some typical parameters such as electrochemically active surface area, double-layer capacitance, potential range in the working media given, heterogeneous rate constant, charge-transfer coefficient, exchange current density, and open-circuit potential. The whole study with ShPEs was then completed with three different examples of possible electroanalytical applications, confirming that the carbon paste-like configuration with powdered shungite represents an environmentally friendly (green) and low-cost electrode material with good stability in mixed aqueous-organic mixtures, and hence with interesting prospects in electroanalysis of biologically active organic compounds. It seems that similar analytical parameters of the already established variants of carbon paste electrodes can also be expected for their shungite analogues.

Electrochemically Induced Templated Sol-gel Deposition of Mesoporous Silica and Nanocomposites: The New Kid on the ECiD Block

A relatively new member of the group of electrochemically induced deposition is that of templated sol-gel deposition. Uniform and smooth mesoporous silica thin films were first fabricated by an ECiD process nicknamed electrochemically assisted self-assembly or EASA, introduced by Walcarius et al. The addition of cetyltrimethylammonium bromide or CTAB as organic template molecules to the tetraethyl orthosilicate (TEOS) sol-gel precursor solution resulted in silica thin films with highly ordered, hexagonal arrays of vertical mesopores of 2–3 nm in diameter. These films have been proposed for applications in electroanalysis and sensors where effects such as pre-concentration or perm selectivity have been exploited. Their synthesis combines the well-established field of templated sol-gel synthesis with an electrochemically induced deposition process. To prevent spontaneous gel formation, the silica sol-gel precursor solution has a mildly acidic pH which kinetically inhibits the gelation reaction. Only when a cathodic potential/current is applied to electrogenerate OH- ions from the pro-base (water mostly), the gelation reaction is catalyzed by the local increase in pH, resulting in the growth of silica gel films on the electrode. We will first review the principles of sol-gel reactions, before proceeding to details of ECiD of sol-gel films.

A Current Averaging Strategy for Maximizing Analyte and Minimizing Redox Interference Signals with Square Wave Voltammetry.

Square wave voltammetry (SWV) is commonly used in electroanalytical applications to enhance analyte faradaic signals and minimize nonfaradaic processes. However, little attention is given as to how best use SWV to minimize faradaic interference signals that arise from redox species present in solution that have redox potentials that convolute with that of the analyte. In conventional SWV, a series of current-time (i-t) transients are collected, and i is averaged over a specified window of each transient (potentiostat dependent). This average i is reported against the electrode potential, E. As the i-t response is governed by the type of electron transfer reaction under investigation, we show how by collecting all i-t data and through judicious choice of the current averaging window, it is possible to enhance the analyte response while at the same time reducing the interferent signal. We look at three different electron transfer reactions, fast electron transfer outer sphere, metal electrodeposition/stripping, and surface-confined proton-coupled electron transfer (PCET) and demonstrate different i-t behaviors in SWV, visually aided by the use of 3D i-t-E plots. In the case of PCET quinone-based voltammetric sensing of pH in the presence of a heavy metal (here Cu2+), we show that the use of a much earlier current averaging window (2-10% of the i-t response) results in the pH signal being clearly distinguished from that of the overlapping heavy metal.

LDH-Based Voltammetric Sensors.

Layered double hydroxides (LDHs), also named hydrotalcite-like compounds, are anionic clays with a lamellar structure which have been extensively used in the last two decades as electrode modifiers for the design of electrochemical sensors. These materials can be classified into LDHs containing or not containing redox-active centers. In the former case, a transition metal cation undergoing a reversible redox reaction within a proper potential window is present in the layers, and, therefore, it can act as electron transfer mediator, and electrocatalyze the oxidation of an analyte for which the required overpotential is too high. In the latter case, a negatively charged species acting as a redox mediator can be introduced into the interlayer spaces after exchanging the anion coming from the synthesis, and, again, the material can display electrocatalytic properties. Alternatively, due to the large specific surface area of LDHs, molecules with electroactivity can be adsorbed on their surface. In this review, the most significant electroanalytical applications of LDHs as electrode modifiers for the development of voltammetric sensors are presented, grouping them based on the two types of materials.

Recent Trends in Therapeutic and Electroanalytical Applications of Boron-Doped Diamond Sensors

Abstract:: In recent years, research and development efforts have been heavily focused on conductive diamond electrodes for electrochemical applications. Such initiatives may have been spurred by their broad potential window, low background current, chemical inertness, and mechanical robustness. Compared to other carbon-based materials, conducting diamond can oxidize several analytes before the breakdown of water in aqueous electrolytes. Since the evolution of oxygen and hydrogen does not obstruct the analysis, this is significant for the detection and/or identification of species in solution. As a result, conductive diamond electrodes expand the application of electrochemical detection and make it possible to use them for analytes that are incompatible with traditional electrode materials. Fabricating boron-doped diamond films via chemical vapor deposition on different substrates is of special interest. This article highlights the therapeutic and electroanalytical applications of boron-doped diamond electrodes in various aspects in addition to the synthetic strategies to obtain Boron Doped Diamond Electrodes (BDDE), the cost-effectiveness of BDD and its in-vivo compatibility that will help the analytical researchers to learn almost everything about the previous studies done on BDDE and encourage them to work more efficiently in this research field.

Voltammetric behavior of solifenacin succinate on gold, glassy carbon and boron-doped diamond electrodes: Stability testing and determination

The anticholinergic drug, solifenacin, is frequently used for the treatment of the urological tract for urinary incontinence, and urinary frequency. The development of reliable and effective solifenacin electrochemical sensors is of great importance for the pharmaceutical industry and clinical practice. In this work, the electrochemical behavior of solifenacin succinate (SOL) was studied using three different working electrodes: gold (Au), glassy carbon (GCE) and boron-doped diamond electrode (BDDE). The cyclic voltammetric (CV) measurements performed in 0.05 M NaHCO3 indicated that the SOL oxidation process is irreversible and diffusion-controlled at all investigated working electrodes. Afterwards, the testing of SOL electrochemical stability and the possibility of its electrochemical degradation was performed at the Au electrode by the cycling of the potential during 3 h and continuously to 6 h. It was shown that the SOL was electrochemically transformed into another electroactive species and its degradation was excluded. For electroanalytical application, the anodically pretreated BDDE (+2.0 V; 30 s) was selected. Various experimental parameters were optimized, including the pH of the aqueous Britton-Robinson (B-R) buffer as a supporting electrolyte (from pH 2.0 to 11.98) and the most intensive peak of the target analyte was at pH 11.0, so this pH value was chosen as the optimum for further measurements. Based on the correlation of the SOL peak intensity and different concentrations, the developed differential pulse voltammetric (DPV) method was characterized by a linear concentration range from 0.041 to 2.50 µM, with a correlation coefficient of 0.999, and a relative standard deviation of 0.3 %. Taking into account the sensitivity of the developed DPV method towards the electrochemical oxidation of SOL, a very low detection limit of 0.012 µM in the model system was achieved. The BDDE showed adequate selectivity for SOL in the presence of the investigated interferents. The obtained results indicate that the BDDE with an optimized DPV method could be applied for the trace-level electroanalytical determination of SOL in human urine sample with excellent recovery and reproducibility.

Electroanalytical application of phenol-functionalized reduced graphene oxide produced using gallic acid in a single step

This study introduces a simple one-step approach for synthesizing phenol-functionalized reduced graphene oxide for electroanalytical purposes, just using gallic acid (GA) and graphene oxide (GO). GA serves as both a reductant for GO and a stabilizing, functionalizing agent, introducing phenolic groups to the nanomaterial. This functionalization imparts remarkable attributes to the nanomaterial, allowing complete dispersion in aqueous solutions and tuning of its electrochemical performance, making it very convenient for electrode modification. The resulting nanomaterials (GA-rGO) underwent characterization through UV–visible, Fourier-transform infrared (FTIR), and Raman spectroscopies, as well as scanning electron microscopy (SEM). Glassy carbon electrodes modified with aqueous dispersions of these nanomaterials (GA-rGO/GCE) were employed in voltammetric experiments to evaluate the optimal dispersion composition for electroanalytical application.These GA-rGO/GCE displayed high electrocatalytic activity for the electrochemical oxidation of relevant clinical and environmental analytes. The unique functionalization of GA-rGO facilitated the selective accumulation of dopamine (DA) and uric acid (UA) on the electrode surface, even in the presence of significant amounts of ascorbic acid (AA) in mixtures. Under the specified conditions, voltammetric currents display linear increments over the concentration ranges of 3.0 x 10-7 M to 2.0 x 10-5 M for DA and 7.0 x 10-6 M to 1.0 x 10-4 M for UA. The sensor demonstrated a low detection limit of 0.090 and 2.1 μM for DA and UA, respectively. The reliability of the electroanalytical performance of the proposed sensor in real samples was demonstrated by the quantification of DA in medications, as well as DA and UA in human urine samples, yielding recovery values between 82 % and 105 %, with relative standard deviation below 11 %.

Fabrication of a graphite-paraffin carbon paste electrode and demonstration of its use in electrochemical detection strategies.

Electrochemical detection methods hold many advantages over their optical counterparts, such as operation in complex sample matrices, low-cost and high volume manufacture and possible equipment miniaturisation. Despite these advantages, the use of electrochemical detection is currently limited in the clinical setting. There is a wide range of potential electrode materials, selected for optimal signal-to-noise ratios and reproducibility when detecting target analytes. The use of carbon paste electrodes (CPEs) for electrochemical detection can be limited by their analytical performance, however they remain very attractive due to their low cost and biocompatibility. This paper presents the fabrication of an easy-to-make and use graphite powder/paraffin wax paste combined with a substrate produced via additive manufacturing and confirms its functionality for both direct and indirect electrochemical measurements. The produced CPEs enable the direct voltammetric detection of hexaammineruthenium(III) chloride and dopamine at an experimental limit of detection (ELoD) of 62.5 μM. The key inflammatory biomarker Interleukin-6 through an enzyme-linked immunosorbant assay (ELISA) was also quantified, yielding a clinically-relevant ELoD of 150 pg ml-1 in 10% human serum. The performance of low-cost and easy-to-use CPEs obtained in 0.5 hours is showcased in this study, demonstrating the platform's potential uses for point-of-need electroanalytical applications.

Electrocatalytic Amplified Sensor For Determination of Ofloxacin Using Zn2SnO4/Reduced Graphene Oxide Composite As Surface-Modifying Agent

This study describes an electroanalytical approach for the quantification of ofloxacin (OFL) through an electrochemical sensor based on a glassy carbon electrode modified with composite material (Zn2SnO4-rGO/GCE) using square wave voltammetry. Zn2SnO4 was synthesized by hydrothermal treatment and characterized by X-ray diffraction, Fourier-transform infrared and Raman spectroscopy and scanning electron microscopy. The analysis suggests a synergistic effect between the composite material, indicating irreversible oxidation of OFL in its protonated form (OFL+), involving two electrons. The electroanalytical methodology was successfully applied to determine OFL in ophthalmic solutions samples, achieving recovery rates ranging from 98.03% to 104.91%. Furthermore, it demonstrated high stability in both repeatability (RSD = 3.20%, n = 12) and reproducibility (RSD = 4.64%, n = 7), with no observed interference when additional substances were added. These results suggest the potential electroanalytical application of Zn2SnO4 and recommend the developed methodology as an alternative tool for OFL determination in commercial pharmaceutical samples.