Detection of Perfluorooctanoic and Perfluorodecanoic Acids on a Graphene-Based Electrochemical Sensor Aided by Computational Simulations.

Perfluoroalkyl carboxylic acids (PFCAs) exhibit high chemical and thermal stability, rendering them versatile for various applications. However, their notable toxicity poses environmental and human health concerns. Detecting trace amounts of these chemicals is crucial to mitigate risks. Electrochemical sensors surpass traditional methods in sensitivity, selectivity, and cost-effectiveness. In this study, a graphene nanosheet-based sensor was developed for detecting perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA). Using the Hummer method, graphene nanosheets were synthesized and characterized in terms of morphology, structural ordering, and surface topology. Ab initio molecular dynamics simulations determined the molecular interaction of per- and poly-fluoroalkyl substances (PFASs) with the sensor material. The sensor exhibited high sensitivity (50.75 µA·µM-1·cm-2 for PFOA and 29.58 µA·µM-1·cm-2 for PFDA) and low detection limits (10.4 nM for PFOA and 16.6 nM for PFDA) within the electrode dynamic linearity range of 0.05-500.0 µM (PFOA) and 0.08-500.0 µM (PFDA). Under optimal conditions, the sensor demonstrated excellent selectivity and recovery in testing for PFOA and PFDA in environmental samples, including spiked soil, water, spoiled vegetables, and fruit samples.

Biomass-derived carbon nanomaterials for sensor applications.

In recent years, an increasing amount of attention has been paid to utilizing dedicated waste biomass as a sustainable, cheap, and abundant fuel and material source. There is a tremendous opportunity for maximizing energy production by applying different reliable waste biomass as a renewable, affordable, and excellent resource. As a result of renewable hydrocarbons such as biomass, bioenergy is produced, green chemicals are manufactured, and carbon materials are made. Furthermore, biomass can be utilized as a source of advanced carbon materials. Carbon materials derived from biomass can also be used to support catalysts in fuel cells with polymer electrolyte membranes. For the fabrication of electrochemical sensors, porous carbonaceous materials generated from biomass are highly advised owing to their specific qualities, including regenerative nature, affordability, distinctive structure, and sustainability. The surface morphology of the sensor, especially its pore volume, surface area, and pore size affects both its electrochemical and catalytic activity. Metal nanoparticle activation, doping, and dispersion are just a few of the methods that may be used to improve the performance of sensors. To detect a variety of target analytes, such as biomolecules, metal ions, contaminants, food additives, and flavonoids, some of the key or seminal advances in the field of biomass-derived carbonaceous compounds are discussed. The materials and composites made of biomass-derived carbon will be in-depth examined, evaluated, and compared in this review. The associated technological difficulties are also discussed, and future research areas are suggested for use in practical applications. Nano carbon materials have several integrated advantages, including good electrical conductivity, structural and chemical flexibility, reduced chemical functionalization, and bulk production potential, making them viable candidates for various electrochemical processes. In the coming years, bio-carbon production from waste biomass is expected to gain rapid scientific and industrial interest because it will be used in electrochemical devices and rechargeable batteries. We emphasize the variety of waste biomass precursors that are accessible, as well as the recent developments in the manufacture of bio-carbon. Carbonaceous nanoparticles generated from biomass have shown potential for use in fuel cells, bioimaging, medicinal delivery, carbon fixation, catalysis, and gas sensors. Interestingly, this article has covered these nanomaterials' new and innovative energy conversion and storage services. Finally, the remaining difficulties, perspective views, and potential research trajectories in the area are described.

Sodium Dodecyl Sulfate-Mediated Graphene Sensor for Electrochemical Detection of the Antibiotic Drug: Ciprofloxacin.

The present study involves detecting and determining CIP by a new electrochemical sensor based on graphene (Gr) in the presence of sodium dodecyl sulfate (SDS) employing voltammetric techniques. Surface morphology studies of the sensing material were analyzed using a scanning electron microscope (SEM) and atomic force microscope (AFM). In the electroanalysis of CIP at the developed electrode, an enhanced anodic peak response was recorded, suggesting the electro-oxidation of CIP at the electrode surface. Furthermore, we evaluated the impact of the electrolytic solution, scan rate, accumulation time, and concentration variation on the electrochemical behavior of CIP. The possible electrode mechanism was proposed based on the acquired experimental information. A concentration variation study was performed using differential pulse voltammetry (DPV) in the lower concentration range, and the fabricated electrode achieved a detection limit of 2.9 × 10-8 M. The proposed sensor detected CIP in pharmaceutical and biological samples. The findings displayed good recovery, with 93.8% for tablet analysis and 93.3% to 98.7% for urine analysis. The stability of a developed electrode was tested by inter- and intraday analysis.

Glucose Incorporated Graphite Matrix for Electroanalysis of Trimethoprim.

The antibiotic drug trimethoprim (TMP) is used to treat bacterial infections in humans and animals, and frequently TMP is used along with sulfonamides. However, a large portion of TMP is excreted in its active state, which poses a severe problem to humans and the environment. A sensitive, rapid, cost-effective analytical tool is required to monitor the TMP concentration in biological and environmental samples. Hence, this study proposed an analytical methodology to analyze TMP in clinical, biological and environmental samples. The investigations were carried out using a glucose-modified carbon paste electrode (G-CPE) employing voltammetric techniques. Electrochemical behavior was examined with 0.5 mM TMP solution at optimum pH 3.4 (Phosphate Buffer Solution, I = 0.2 M). The influence of scan rate on the electro-oxidation of TMP was studied within the range of 0.05 to 0.55 V/s. The effect of pH and scan rate variations revealed proton transfer during oxidation. Moreover, diffusion phenomena governed the irreversibility of the electrode reaction. A probable and suitable electrode interaction and reaction mechanism was proposed for the electrochemical oxidation of TMP. Further, the TMP was quantitatively estimated with the differential pulse voltammetry (DPV) technique in the concentration range from 9.0 × 10-7 to 1.0 × 10-4 M. The tablet, spiked water and urine analysis demonstrated that the selected method and developed electrode were rapid, simple, sensitive, and cost-effective.

Direct and Sensitive Electrochemical Evaluation of Pramipexole Using Graphitic Carbon Nitride (gCN) Sensor.

Pramipexole (PMXL) belongs to the benzothiazole class of aromatic compounds and is used in treating Parkinson's disease; however, overdosage leads to some abnormal effects that could trigger severe side effects. Therefore, it demands a sensitive analytical tool for trace level detection. In this work, we successfully developed an electrochemical sensor for the trace level detection of PMXL, using the voltammetric method. For the analysis, graphitic carbon nitride (gCN) was opted and synthesized by using a high-temperature thermal condensation method. The synthesized nanoparticles were employed for surface characterization, using transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) techniques. The electrochemical characterization of the material was evaluated by using the electrochemical impedance spectroscopy (EIS) technique to evaluate the solution-electrode interface property. The cyclic voltammetry (CV) behavior of PMXL displayed an anodic peak in the forward scan, indicating that PMXL underwent electrooxidation, and an enhanced detection peak with lower detection potential was achieved for gCN-modified carbon paste electrode (gCN·CPE). The influence of different parameters on the electrochemical behavior was analyzed, revealing the diffusion governing the electrode process with an equal number of hydronium ions and electron involvement. For the fabricated gCN·CPE, good linearity range was noticed from 0.05 to 500 µM, and a lower detection limit (LD) of 0.012 µM was achieved for the selected concentration range (0.5 to 30 µM). Selectivity of the electrode in PMXL detection was investigated by conducting an interference study, while the tablet sample analysis demonstrates the sensitive and real-time application of the electrode. The good recovery values for the analysis illustrate the efficiency of the electrode for PMXL analysis.