Search Results (19)

Hollow porous AuAg nanospheres (AuAg HPNSs) were obtained through a simple solvothermal synthesis, complemented by a dealloying strategy. The hollow interior, open pore voids, and integral interconnected skeleton shell in AuAg HPNSs are beneficial for providing sufficient electrolyte diffusion and contacts, abundant active sites, and efficient electron transport. This specific structure and the favorable alloy synergism contribute to the superior electrocatalytic activity toward dopamine (DA) and acetaminophen (AC). AuAg HPNSs show high sensitivity, good selectivity, excellent sensing durability, and outstanding repeatability for amperometric assays of AC and DA. In particular, the AuAg-based sensors achieve effective ultrasensitive simultaneous analyses of AC and DA, exhibiting the characteristics of the wide linear range and low detection limit. With their prominent electrocatalytic activity and simple preparation methods, AuAg HPNSs present broad application prospects for constructing a highly responsive electrochemical sensing system. Full article

In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect antipyretic drugs with high sensitivity and selectivity. The electrochemical determination of acetaminophen (PCT) was studied with strontium molybdate with a functionalized carbon nanotube (SrMoO₄@f-CNF) nanocomposite. The SrMoO₄@f-CNF nanocomposite was produced by a facial hydrothermal followed by sonochemical treatment, resulting in a significant enhancement in the PCT determination. The sonochemical process was applied to incorporate SrMoO₄ nanoparticles over f-CNF, enabling a network-like structure. Moreover, the produced SrMoO₄@f-CNF composite structural, morphological, and spectroscopic properties were confirmed with XRD, TEM, and XPS characterizations. The synergistic effect between SrMoO₄ and f-CNF contributes to the lowering of the charge transfer resistance ($R_{ct}=85\Omega ·{\mathrm{c}\mathrm{m}}^2$), a redox potential of $E_{pc}=0.15\mathrm{V}$ and $E_{pa}=0.30\mathrm{V}$ (vs. Ag/AgCl), and a significant limit of detection (1.2 nM) with a wide response range of 0.01–28.48 µM towards the PCT determination. The proposed SrMoO₄@f-CNF sensor was studied with differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques and demonstrated remarkable electrochemical properties with a good recovery range in real-sample analysis. Full article

This work devised a simple glycerol-assisted synthesis of a low-Cu²⁺-doped CoFe₂O₄ and the electrochemical detection of acetaminophen (AC). During the synthesis, several polyalcohols were tested, indicating the efficiency of glycerin as a cosolvent, aiding in the creation of electrode-modifier nanomaterials. A duration of standing time (eight hours) before calcination produces a decrease in the secondary phase of hematite. The synthesized material was used as an electrode material in the detection of AC. In acidic conditions (pH 2.5), the limit of detection (LOD) was 99.4 nM, while the limit of quantification (LOQ) was found to be (331 nM). The relative standard deviation (RSD), 3.31%, was computed. The enhanced electrocatalytic activity of a low-Cu²⁺-doped CoFe₂O₄-modified electrode Cu_0.13Co_0.87Fe₂O₄/GCE corresponds extremely well with its resistance R_ct, which was determined using the electrochemical impedance spectroscopy (EIS) technique and defined its electron transfer capacity. The possibility of a low-Cu²⁺-doped CoFe₂O₄ for the electrochemical sensing of AC in human urine samples was studied. The recovery rates ranging from 96.5 to 101.0% were obtained. These findings suggested that the Cu_0.13Co_0.87Fe₂O₄/GCE sensor has outstanding practicability and could be utilized to detect AC content in real complex biological samples. Full article

Electrochemical portable sensing systems can offer viable support in the analysis of environmental contaminants due to the compactness of their electronic components and overall simplicity of their detection principles. In the present work, a new electrochemical portable platform (EPP) with miniaturized chip-integrated gold electrodes was developed and applied in the detection of the drug acetaminophen (APAP) as a model analyte. The produced miniaturized chip-integrated gold electrodes were first characterized via atomic force and scanning electron microscopy and integrated into the EPP, and subsequently the complete set-up was tested for electrochemical detection of APAP. The results showed adequate performance of the developed EPP when compared to a traditional electrochemical system under optimal conditions (pH 8, deposition potential 0.1 V, deposition time 240 s and scan rate of 50 mV.s⁻¹), with a sensitivity of 1.6 μA.mM⁻¹ and limit of detection of 67 µM. The EPP was validated in river and wastewater samples, achieving recoveries ranging from 93.0 to 96.6%. Full article

Based on the modification of carbon paste electrode with NiCo₂O₄ nanoplates and 1-hexyl-3-methylimidazolium tetrafluoroborate, a new electrochemical sensing platform for the sensing of favipiravir (a drug with potential therapeutic efficacy in treating COVID-19 patients) in the presence of acetaminophen was prepared. For determining the electrochemical behavior of favipiravir, cyclic voltammetry, differential pulse voltammetry, and chronoamperometry have been utilized. When compared to the unmodified carbon paste electrode, the results of the cyclic voltammetry showed that the proposed NiCo₂O₄ nanoplates/1-hexyl-3-methylimidazolium tetrafluoroborate/carbon paste electrode had excellent catalytic activity for the oxidation of the favipiravir in phosphate buffer solution (pH = 7.0). This was due to the synergistic influence of 1-hexyl-3-methylimidazolium tetrafluoroborate (ionic liquid) and NiCo₂O₄ nanoplates. In the optimized conditions of favipiravir measurement, NiCo₂O₄ nanoplates/1-hexyl-3-methylimidazolium tetrafluoroborate/carbon paste electrode had several benefits, such as a wide dynamic linear between 0.004 and 115.0 µM, a high sensitivity of 0.1672 µA/µM, and a small limit of detection of 1.0 nM. Furthermore, the NiCo₂O₄ nanoplates/1-hexyl-3-methylimidazolium tetrafluoroborate/carbon paste electrode sensor presented a good capability to investigate the favipiravir and acetaminophen levels in real samples with satisfactory recoveries. Full article

Acetaminophen (N-acetyl-p-aminophenol, APAP) is regularly used for antipyretic and analgesic purposes. Overdose or long-term exposure to APAP could lead to liver damage and hepatotoxicity. In this study, the approach of enhanced electrochemical detection of APAP by nanostructured biomass carbon/silver was developed. Porous biomass carbon derived from Elaeagnus Angustifolia gum was prepared by pyrolysis with co-doping of electron-rich elements of nitrogen, sulfur, and phosphorus. The electrodeposition of silver onto a glassy carbon electrode modified with porous carbon could enhance the sensing signal towards APAP. Two linear ranges from 61 nM to 500 μM were achieved with a limit of detection of 33 nM. The developed GCE sensor has good anti-interference, stability, reproducibility, and human urine sample analysis performance. The silver-enhanced biomass carbon GCE sensor extends the application of biomass carbon, and its facile preparation approach could be used in constructing disposable sensing chips in the future. Full article

In this work, Fe–decorated nitrogen–doped carbon nanospheres are prepared for electrochemical monitoring of acetaminophen. Via a direct pyrolysis of the melamine–formaldehyde resin spheres, the well–distributed Fe–NC spheres were obtained. The as–prepared Fe–NC possesses enhanced catalysis towards the redox of acetaminophen for abundant active sites and high–speed charge transfer. The effect of loading Fe species on the electrochemical sensing of acetaminophen is investigated in detail. The synergistic effect of nitrogen doping along with the above–mentioned properties is taken advantage of in the fabrication of electrochemical sensors for the acetaminophen determination. Based on the calibration plot, the limits of detection (LOD) were calculated to be 0.026 μM with a linear range from 0–100 μM. Additionally satisfactory repeatability, stability, and selectivity are obtained. Full article

Cephalexin (CFX), a first-generation cephalosporin, is used to treat various infectious diseases. Although antibiotics have achieved considerable progress in the eradication of infectious diseases, their incorrect and excessive usage has contributed to various side effects, such as mouth soreness, pregnancy-related pruritus, and gastrointestinal symptoms, including nausea, epigastric discomfort, vomiting, diarrhoea, and haematuria. In addition to this, it also causes antibiotic resistance, one of the most pressing problems in the medical field. The World Health Organization (WHO) claims that cephalosporins are currently the most commonly used drugs for which bacteria have developed resistance. Hence, it is crucial to detect CFX in complex biological matrices in a highly selective and sensitive way. In view of this, a unique trimetallic dendritic nanostructure comprised of cobalt, copper, and gold was electrochemically imprinted on an electrode surface by optimising the electrodeposition variables. The dendritic sensing probe was thoroughly characterised using X-ray photoelectron spectroscopy, scanning electron microscopy, chronoamperometry, electrochemical impedance spectroscopy, and linear sweep voltammetry. The probe displayed superior analytical performance, with a linear dynamic range between 0.05 nM and 10⁵ nM, limit of detection of 0.04 ± 0.01 nM, and response time of 4.5 ± 0.2 s. The dendritic sensing probe displayed minimal response to interfering compounds, such as glucose, acetaminophen, uric acid, aspirin, ascorbic acid, chloramphenicol, and glutamine, which usually occur together in real matrices. In order to check the feasibility of the surface, analysis of a real sample was carried out using the spike and recovery approach in pharmaceutical formulations and milk samples, yielding current recoveries of 93.29–99.77% and 92.66–98.29%, respectively, with RSD < 3.5%. It only took around 30 min to imprint the surface and analyse the CFX molecule, making it a quick and efficient platform for drug analysis in clinical settings. Full article

Because of the widespread acetaminophen usage and the danger of harmful overdosing effects, developing appropriate procedures for its quantitative and qualitative assay has always been an intriguing and fascinating problem. A quick, inexpensive, and environmentally friendly approach based on direct voltage anodic graphite rod exfoliation in the presence of inorganic salt aqueous solution ((NH₄)₂SO₄–0.3 M) has been established for the preparation of nitrogen-doped graphene (exf-NGr). The XRD analysis shows that the working material appears as a mixture of few (76.43%) and multi-layers (23.57%) of N-doped graphenes. From XPS, the C/O ratio was calculated to be 0.39, indicating a significant number of structural defects and the existence of multiple oxygen-containing groups at the surface of graphene sheets caused by heteroatom doping. Furthermore, the electrochemical performances of glassy carbon electrodes (GCEs) modified with exf-NGr for acetaminophen (AMP) detection and quantification have been assessed. The exf-NGr/GCE-modified electrode shows excellent reproducibility, stability, and anti-interfering characteristics with improved electrocatalytic activity over a wide detection range (0.1–100 µM), with a low limit for AMP detection (LOD = 3.03 nM). In addition, the developed sensor has been successfully applied in real sample analysis for the AMP quantification from different commercially available pharmaceutical formulations. Full article

In this paper, Cu nanocolumnar structure electrodes are synthetized using a clean and easy-to-scale-up direct-current magnetron sputtering (DC-MS) technique for non-enzymatic glucose sensing. The nanocolumnar structure increases the active surface area of the deposit, with the nanocolumns showing a mean size diameter of 121.0 nm ± 27.2 and a length of 2.52 µm ± 0.23. A scanning transmission electron (STEM) analysis shows the presence of Cu and a small amount of Cu₂O. The behavior of the electrodes in alkaline environments and the electrochemical affinity of the Cu nanocolumns (CuNCs) towards the electro-oxidation of glucose are investigated using cyclic voltammetry (CV). After performing CV in NaOH solution, the columnar structures present corrosion products containing Cu₂O, as revealed by STEM and X-ray diffraction (XRD) analyses. The amperometric responses of the CuNCs to the successive addition of glucose show a linear range up to 2 mM and a limit of detection of 5.2 µM. Furthermore, the electrodes are free from chloride poisoning, and they are insensitive to dopamine, uric acid, ascorbic acid, and acetaminophen at their physiological concentrations. Full article

In this study, Ni–Co–Te nanocomposites with multi-dimensional hierarchical structure were successfully prepared using a hydrothermal method. Ni–Co–Te nanocomposites used as electrode materials afford enhanced electroactive properties for electrochemical acetaminophen sensing. Field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used to characterize the morphological and structural properties to boost their further promotion in acetaminophen sensing. The electrochemical performance of Ni–Co–Te nanocomposites was characterized by electrochemical measurements (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). The lower electronegativity of the telluride atom and unique structural features of Ni–Co–Te nanocomposites endow the materials with promising performance in acetaminophen sensing (including linear range from 2.5 to 1000 μM, sensitivity of 0.5 μAμM⁻¹cm⁻², limit of detection of 0.92 μM, and excellent selectivity). The results indicated that Ni–Co–Te nanocomposites can serve as promising electrode materials for practical application in electrochemical acetaminophen sensing. Full article

This study used substituted barium hexaferrites, which were previously prepared and reported by the authors, to detect acetaminophen by the modification of a conventional glassy carbon electrode (GCE), which led to promising results. The synthesis of this electrode-modifying material was conducted using a citrate sol gel process. A test synthesis using glycerin and propylene glycol revealed that glycerin produced a better result, while less positive anodic potential values were associated with the electrooxidation of N-acetyl-p-aminophenol (NAP). Excellent electroactivity was exhibited by the cobalt-substituted barium-hexaferrite-nanomaterial-modified electrode. A good linear relationship between the concentration and the current response of acetaminophen (paracetamol) was obtained with a detection limit of (0.255 ± 0.005) µM for the Ba_1.0Co_1.22Fe_11.41O_18.11 GCE, (0.577 ± 0.007) µM for the Ba_1.14Cu_0.82Fe_11.65O_18.02 GCE, and (0.595 ± 0.008) µM for the bare GCE. The levels of NAP in a real sample of urine were quantitatively analyzed using the proposed method, with recovery ranges from 96.6% to 101.0% and 93.9% to 98.4% for the modified electrode with Cobalt-substituted barium hexaferrites (CoF_M) and Copper-substituted barium hexaferrites (CuF_M), respectively. These results confirm the high electrochemical activity of Ba_1.0Co_1.22Fe_11.41O_18.11 nanoparticles and thus their potential for use in the development of sensing devices for substances of pharmaceutical interest, such as acetaminophen (NAP). Full article

A novel hybrid composite of conductive poly(methylene blue) (PMB) and carbon nanotubes (CNT) was prepared for the detection of 5-aminosalicylic acid (5-ASA). Electrosynthesis of PMB with glassy carbon electrode (GCE) or with carbon nanotube modified GCE was done in ethaline deep eutectic solvent of choline chloride mixed with ethylene glycol and a 10% v/v aqueous solution. Different sensor architectures were evaluated in a broad range of pH values in a Britton-Robinson (BR) buffer using electrochemical techniques, chronoamperometry (CA), and differential pulse voltammetry (DPV), to determine the optimum sensor configuration for 5-ASA sensing. Under optimal conditions, the best analytical performance was obtained with CNT/PMB_DES/GCE in 0.04 M BR buffer pH 7.0 in the range 5–100 µM 5-ASA using the DPV method, with an excellent sensitivity of 9.84 μA cm⁻² μM⁻¹ (4.9 % RSD, n = 5) and a detection limit (LOD) (3σ/slope) of 7.7 nM, outclassing most similar sensors found in the literature. The sensitivity of the same sensor obtained in CA (1.33 μA cm⁻² μM⁻¹) under optimal conditions (pH 7.0, E_app = +0.40 V) was lower than that obtained by DPV. Simultaneous detection of 5-ASA and its analogue, acetaminophen (APAP), was successfully realized, showing a catalytic effect towards the electro-oxidation of both analytes, lowering their oxidation overpotential, and enhancing the oxidation peak currents and peak-to-peak separation as compared with the unmodified electrode. The proposed method is simple, sensitive, easy to apply, and economical for routine analysis. Full article

Organically modified ceramic polymers (ORMOCERs) have attracted substantial interest in biomicrofluidic applications owing to their inherent biocompatibility and high optical transparency even in the near-ultraviolet (UV) range. However, the processes for metallization of ORMOCERs as well as for sealing of metallized surfaces have not been fully developed. In this study, we developed metallization processes for a commercial ORMOCER formulation, Ormocomp, covering several commonly used metals, including aluminum, silver, gold, and platinum. The obtained metallizations were systematically characterized with respect to adhesion (with and without adhesion layers), resistivity, and stability during use (in electrochemical assays). In addition to metal adhesion, the possibility for Ormocomp bonding over each metal as well as sufficient step coverage to guarantee conductivity over topographical features (e.g., over microchannel edges) was addressed with a view to the implementation of not only planar, but also three-dimensional on-chip sensing elements. The feasibility of the developed metallization for implementation of microfluidic electrochemical assays was demonstrated by fabricating an electrophoresis separation chip, compatible with a commercial bipotentiostat, and incorporating integrated working, reference, and auxiliary electrodes for amperometric detection of an electrochemically active pharmaceutical, acetaminophen. Full article

Transition-metal nanomaterials are very important to non-enzymatic glucose sensing because of their excellent electrocatalytic ability, good selectivity, the fact that they are not easily interfered with by chloride ion (Cl⁻), and low cost. However, the linear detection range needs to be expanded. In this paper, Cu₂O–bovine serum albumin (BSA) core-shell nanoparticles (NPs) were synthesized for the first time in air at room temperature by a facile and green route. The structure and morphology of Cu₂O–BSA NPs were characterized. The as-prepared Cu₂O–BSA NPs were used to modify the glassy carbon electrode (GCE) in a Nafion matrix. By using cyclic voltammetry (CV), the influence from scanning speed, concentration of NaOH, and load of Cu₂O–BSA NPs for the modified electrodes was probed. Cu₂O–BSA NPs showed direct electrocatalytic activity for the oxidation of glucose in 50 mM NaOH solution at 0.6 V. The chronoamperometry result showed this constructing sensor in the detection of glucose with a lowest detection limit of 0.4 μM, a linear detection range up to 10 mM, a high sensitivity of 1144.81 μAmM⁻¹cm⁻² and reliable anti-interference property to Cl⁻, uric acid (UA), ascorbic acid (AA), and acetaminophen (AP). Cu₂O–BSA NPs are promising nanostructures for the fabrication of non-enzymatic glucose electrochemical sensing devices. Full article