Abstract A very sensitive and ultra‐selective electrochemical sensing device with high conductivity and durability was made using styrene, ethylene glycol dimethacrylate (EGDMA), and functionalised graphene oxide. To construct a mediator‐free, non‐enzymatic sensing probe for the detection of arsenic (v) ions, a recently synthesized sensor was impregnated onto an interdigital electrode (IDE) surface. The newly developed receptors were characterized using Fourier Transmission Infra‐Red (FTIR) and Atomic Force Microscopy (AFM). Under the optimized experimental conditions, sensor showed the lowest detection limit of 0.11 ppb with highest sensitivity (3460 ppb) and a strong linear relationship in the range of 50 ppm–1 ppb of As (v) concentration. The ion imprinting technique is employed to enhance the selectivity of the fabricated sensor. The arsenic sensor is found to be highly selective in the presence of interfering species like AlCl3, FeCl3, and CoCl3 etc. The electrochemical sensor proved to be reliable and could be reused after proper storage, also exhibit a high repeatability response and maintaining of 99 % of its initial sensor response for detection after repeated use of one month to six months. This effort showed excellent results in an electrochemical sensor with sensitivity, selectivity, stability, and reversibility for detecting trace quantities of As (v) in real water samples.

Abstract Wearable electrochemical sensors, which can track various biomarkers in real‐time, is one of the most promising bioanalytical devices in the point of care testing and health management. Sample collection modules, as the important front‐end of the sensors, capture and transfer enough sample so as to achieve real‐time, precise and accurate detection. Noninvasive and minimally invasive techniques for sample collection are highly desired. However, it is still a key challenge to realize a reliable sample acquisition. Herein, we provide an overview on the progress in the sample collection methods for wearable electrochemical sensors. It covers the conventional and emerging methods/structures including reverse iontophoresis, microneedles, as well as microfluidic chips. The working principle, fabrication materials and manufacturing technologies will be introduced in detail. Finally, the present challenges and the development trend in the future of these approaches are also put forward.

Abstract Free acids commonly exist in anhydride and esters because they are unstable and tend to break down into free acids, which affect the quality of subsequent products in industrial production. Phthalic anhydride and ethyl acetate undergo hydrolysis reactions to form phthalic acid and acetic acid. A differential pulse voltammetry method for the determination of phthalic acid and acetic acid was developed with a bare glassy carbon electrode. Phthalic acid and acetic acid caused a new cathodic peak at more positive potential during the reduction of 1,4‐benzoquinone in acetonitrile or aqueous solution. The new peaks are attributed to the drastic increase in pH at the electrode surface caused by the consumption of protons in the benzoquinone reduction reaction. The peak current of the new cathodic peak was dependent on the concentration of phthalic acid and acetic acid but independent of BQ, phthalic anhydride, and ethyl acetate. This method does not cause hydrolysis of anhydride and ester because no external base is introduced. Furthermore, the method is sensitive, rapid, and does not require pretreatment.

Cover picture provided by Dr. Elena Benito-Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point-of-care diagnostics, wearable sensors, and practical applications.

Abstract Microfluidic fuel cells (μFCs) offer a promising avenue for generating energy from glycerol, utilizing flow‐through electrodes to enhance reactant utilization. However, the cathodic reaction must efficiently consume the electrons harvested at the anode side to unlock its full potential. Here, we explore the feasibility of employing liquid oxidants as an alternative to O2 reduction on metal‐free carbon paper (CP) cathodes. We investigated the half‐cell reactions and the energy conversion in a new reusable 3D‐printed μFC. Half‐cell reactions predict spontaneous reactions by coupling glycerol electrooxidation in an alkaline medium with O2, Na2S2O8, and HClO from commercial bleach in an acidic medium. The μFC printed using the stereolithography apparatus technique build microchannels to place the Pt/C/CP anode and CP cathodes. The glycerol/Na2S2O8 μFC delivered a maximum of 32.4 mW cm−2, while glycerol/HClO μFC displayed 55.9 mW cm−2. This research sheds light on the potential of liquid oxidants as effective alternatives to O2 reduction, presenting a pathway toward optimizing μFCs and their practical applications in energy conversion from glycerol.

Abstract The fabrication of a novel bis(tert‐butylaminomethyl)pyridine pincer ligand‐based ionophore in a carbon paste electrode (CPE) matrix for Al3+ ions was investigated. With a Nernstian slope of 20.05±0.27 mV decade−1 and a low detection limit of 1.0×10−7 mol L−1, the electrode demonstrated an excellent response for the Al3+ ion over a broad concentration range from 1.0×10−7 to 1.0×10−1 mol L−1. The formula for the graphite paste that produced the greatest results was 69.44 % graphite, 27.78 % tricresyl phosphate (TCP) binder, and 2.78 % ionophore. This pincer ligand‐based electrode worked well with aqueous Al3+ solutions that had pH values between 2.5 and 5.5. It may be used for at least 4 months without any detectable potentials digression and has a reasonably quick response time (5 s). The suggested graphitic paste electrode demonstrated strong Al3+ ion selectivity over a broad range of other cations. The isothermal coefficient of the electrode, which was determined to be 0.2884×10−3 V °C−1, was calculated by looking at the impact of test solution temperature on electrode potentials. The suggested electrode was also applied to non‐aqueous media with an aqueous‐non‐aqueous volume ratio of up to 75 : 25. The data acquired using this CPE as an indicator electrode for the potentiometric measurement of Al3+ ions in several actual samples was equivalent to that attained using atomic absorption spectroscopy (AAS).

Abstract Crohn's disease, a chronic inflammatory disorder affecting the gastrointestinal tract, is on the rise, posing significant health challenges due to its potential long‐term impact on intestinal health. Early and accurate detection of this disease is crucial for effective treatment. This study introduces an innovative approach to diagnosing Crohn's disease by utilizing a rapid and precise biosensor system as an alternative to conventional detection techniques. Utilization of an S100 A8 targeting aptamer for the specific identification of calprotectin, a well‐established biomarker associated with Crohn's disease was used as a biorecognition receptor. The aptamer is immobilized on gold nanoparticles via cysteamine and avidin to construct a biosensor. The biosensor was compared with traditional quantitative lateral‐flow tests (QLFA). The developed biosensor demonstrates that detection in 900 seconds. Performance parameters, including a limit of detection (LOD) as 5.57 μg/g and a limit of quantification (LOQ) as 16.89 μg/g, are determined through electrochemical impedance spectroscopy (EIS). Accordingly, the calibration curve equation was calculated as y=3.9736x + 1570.4 and the regression coefficient was found as R2=0.9917. These results showed that biosensor‘s capability to reliably measure calprotectin levels in real samples.

Abstract 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.

Cover picture provided by Dr. Elena Benito-Peña and Dr. Susana Campuzano. Electroanalysis covers all branches of electroanalytical chemistry, including both fundamental and application papers as well as reviews dealing with analytical voltammetry, potentiometry, new electrochemical sensors and detection schemes, nanoscale electrochemistry, advanced electromaterials, nanobioelectronics, point-of-care diagnostics, wearable sensors, and practical applications.

Abstract In this paper, we present gold‐plating polycarbonate (PC) microchannels. The fabrication of the gold microfluidic channels is achieved by tuning the sequence of reagent insertion into milled and closed submillimeter PC system channels. The resulting gold surface can be utilized in many applications where the benefits of microfluidics, (bio)chemistry of surfaces, and electrochemistry can be combined.Here, we combine the advantages of electrochemistry with microfluidics by mixing the gold sensor with microfluidics. This approach differs from the classic one – the sensor will undergo modifications (e. g., shape and size) depending on the specific scientific problem and will be designed individually; hence its characteristics will be changed. Our goal in this work is to indicate new possibilities for combining two methodologies – electrochemistry and microfluidics. In our work, we emphasize that it confirms the validity of our chosen concept (proof‐of‐concept).In this work, we present one such application, the use of a gold microfluidic channel as a working electrode (WE). We describe the microchip‘s construction and electrochemical characterization, including the gold flow‐through WE, the Ag/AgCl wire pseudo‐reference, and the Pt auxiliary electrode. The measured current is the result of the flow through a rectangular duct of the gold microchannel electrode embedded in the four walls of the chip.