Effective and reliable platform for nonenzymatic nanomolar-range quinol detection in water samples using ceria doped polypyrrole nanocomposite embedded on graphitic carbon nitride nanosheets

Graphitic carbon nitride-based electrochemical sensors: A comprehensive review of their synthesis, characterization, and applications

Graphitic carbon nitride (g-C3N4) has garnered much attention as a promising 2D material in the realm of electrochemical sensors. It contains a polymeric matrix that can serve as an economical and non-toxic electrode material for the detection of a diverse range of analytes. However, its performance is impeded by a relatively limited active surface area and inherent instability. Although electrochemistry involving metal-doped g-C3N4 nanomaterials is rapidly progressing, it remains relatively unexplored. The metal doping of g-C3N4 augments the electrochemically active surface area of the resulting electrode, which has the potential to significantly enhance electrode kinetics and bolster catalytic activity. Consequentially, the main objective of this review is to provide insight into the intricacies of synthesizing and characterizing metal-doped g-C3N4. Furthermore, we comprehensively delve into the fundamental attributes of electrochemical sensors based on metal-doped g-C3N4, with a specific focus on healthcare and environmental applications. These applications encompass a meticulous exploration of detecting biomolecules, drug molecules, and organic pollutants.

Highly enhanced chloramphenicol adsorption performance of MIL-53-NH2(Al)-derived porous carbons modified with tannic acid

The worldwide demand for antibiotics has experienced a notable surge, propelled by the repercussions of the COVID-19 pandemic and advancements in the global healthcare sector. A prominent challenge confronting humanity is the unregulated release of antibiotic-laden wastewater into the environment, posing significant threats to public health. The adoption of affordable carbon-based adsorbents emerges as a promising strategy for mitigating the contamination of antibiotic wastewater. Here, we report the synthesis of novel porous carbons (MPC) through a direct pyrolysis of MIL-53-NH2(Al) and tannic acid (TANA) under N2 atmosphere at 800 °C for 4 h. The effect of TANA amount ratios (0%-20%, wt wt-1) on porous carbon structure and adsorption performance was investigated. Results showed that TANA modification resulted in decreased surface area (1,600 m2 g-1-949 m2 g-1) and pore volume (2.3 cm3 g-1-1.7 cm3 g-1), but supplied hydroxyl functional groups. Adsorption kinetic, intraparticle diffusion, and isotherm were examined, indicating the best fit of Elovich and Langmuir models. 10%-TANA-MPC obtained an ultrahigh adsorption capacity of 564.4 mg g-1, which was approximately 2.1 times higher than that of unmodified porous carbon. 10%-TANA-MPC could be easily recycled up to 5 times, and after reuse, this adsorbent still remained highly stable in morphology and surface area. The contribution of H bonding, pore-filling, electrostatic and π-π interactions to chloramphenicol adsorption was clarified. It is recommended that TANA-modified MIL-53-NH2(Al)-derived porous carbons act as a potential adsorbent for removal of pollutants effectively.

Voltammetric nano-molar range quantification of agrochemical pesticide using needle-like strontium pyrophosphate embedded on sulfur doped graphitic carbon nitride electrocatalyst

The development of a viable sensor for agrochemical pesticides requires the assessment of trace levels. To achieve this, we developed a diphenylamine (DPA) sensor using needle-like strontium pyrophosphate embedded in sulfur-doped graphitic carbon nitride (SrPO/SCN). We obtained needle-like SrPO/SCN nanocomposite through co-precipitation followed by ultrasonication. The formation of the SrPO/SCN nanocomposite was verified through FT-IR, XRD, XPS, SEM-EDX, and HR-TEM analyses. Additionally, we explored their electrochemical behavior towards DPA using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). The SrPO/SCN nanocomposite-modified electrode exhibited a higher anodic peak current (15.47 µA) than those of the other modified and unmodified electrodes. Under optimal experimental conditions, SrPO/SCN/GCE demonstrated a good limit of detection (0.009 µmol/L), dynamic linear range (0.05-98 µmol/L), and sensitivity (0.36 µAµM-1cm-2). Furthermore, the developed sensor exhibited excellent reproducibility, selectivity, and stability, and successfully detected DPA in real samples, including pear and apple samples, with good recoveries.

Using Nanomaterials as Excellent Immobilisation Layer for Biosensor Design

The endless development in nanotechnology has introduced new vitality in device fabrication including biosensor design for biomedical applications. With outstanding features like suitable biocompatibility, good electrical and thermal conductivity, wide surface area and catalytic activity, nanomaterials have been considered excellent and promising immobilisation candidates for the development of high-impact biosensors after they emerged. Owing to these reasons, the present review deals with the efficient use of nanomaterials as immobilisation candidates for biosensor fabrication. These include the implementation of carbon nanomaterials-graphene and its derivatives, carbon nanotubes, carbon nanoparticles, carbon nanodots-and MXenes, likewise their synergistic impact when merged with metal oxide nanomaterials. Furthermore, we also discuss the origin of the synthesis of some nanomaterials, the challenges associated with the use of those nanomaterials and the chemistry behind their incorporation with other materials for biosensor design. The last section covers the prospects for the development and application of the highlighted nanomaterials.

Barium titanate nanoparticle-based disposable sensor for nanomolar level detection of the haematotoxic pollutant quinol in aquatic systems

Barium titanate nanoparticles synthesized by a simple co-precipitation method and applied for the electrochemical detection of quinol.

An electrochemical sensor based on a Co3O4-ERGO nanocomposite modified screen-printed electrode for detection of uric acid in artificial saliva

In this study, we report the fabrication of a nanocomposite consisting of Co₃O₄ nanoparticles (Co₃O₄ NPs) and electrochemically reduced graphene oxide (ERGO) on a screen-printed electrode (SPE) and its sensing performance in the electrochemical detection of uric acid (UA). The surface modification of the electrode was confirmed by using a variety of characterization techniques (FE-SEM, XRD, AFM, EDX, WCA, FTIR, and Raman spectroscopy). In addition, the surface modification was electrochemically characterized step by step through CV, EIS and DPV techniques, and the results showed that the Co₃O₄-ERGO nanocomposite exhibited highly sensitive and selective sensing performance towards the oxidation of UA in 0.1 M (pH 7.0) phosphate buffer solution (PBS). The sensor (Co₃O₄-ERGO/SPE) signals were observed to be linear to the UA concentration in the range of 5 μM to 500 μM (R² = 0.9985). After revealing its other performance characteristics, such as repeatability, reproducibility, stability, sensitivity, and selectivity, the sensor was successfully applied to the analysis of UA in artificial saliva samples.