Recent advances in applications of surfactant‐based voltammetric sensors

Highly sensitive electrochemical determination of agomelatine in biological samples based on Cu nanoparticles/Schiff base network1 modified glassy carbon electrode: DFT and experimental studies

In this study, a nanocomposite of copper nanoparticles incorporated into a covalent organic framework (Cu@SNW1) was synthesized and characterized by various approaches such as scanning electron microscopy, cyclic voltammetry, X-ray diffraction, electrochemical impedance spectroscopy, and energy dispersive X-ray spectroscopy. The interaction between the nanocomposite and agomelatine (AGM) was investigated through density functional theory computations. The results indicated that the nanocomposite displays electrocatalytic properties towards AGM and their interactions are both experimentally and thermodynamically viable. The synthesized nanocomposite was employed as an electrocatalytic modifier for the highly selective and sensitive square wave anodic stripping voltammetric detection of AGM. Experimental parameters including; pH, deposition time, modifier concentration, and deposition potential were fine-tuned using the Box-Behnken experimental design strategy. Under the optimal conditions, a linear correlation was established between the anodic peak current of AGM and its concentration across two linear ranges, 0.007-1.00 μmol L-1 and 1.00-6.50 μmol L-1. The method demonstrated a limit of detection of 0.002 μmol L-1 under the optimized parameters. Furthermore, the proposed method exhibited high sensitivity and selectivity in determining AGM in urine, serum, and saliva samples.

Application of surfactants in the electrochemical sensing and biosensing of biomolecules and drug molecules

Realizing sensitive and efficient detection of biomolecules and drug molecules is of great significance. Among the detection methods that have been proposed, electrochemical sensing is favored for its outstanding advantages such as simple operation, low cost, fast response and high sensitivity. The unique structure and properties of surfactants have led to a wide range of applications in the field of electrochemical sensors and biosensors for biomolecules and drug molecules. Through the comparative analysis of reported works, this paper summarizes the application modes of surfactants in electrochemical sensors and biosensors for biomolecules and drug molecules, explores the possible electrocatalytic mechanism of their action, and looks forward to the development trend of their applications. This review is expected to provide some new ideas for subsequent related research work.

Smart and emerging point of care electrochemical sensors based on nanomaterials for SARS-CoV-2 virus detection: Towards designing a future rapid diagnostic tool

In the recent years, researchers from all over the world have become interested in the fabrication of advanced and innovative electrochemical and/or biosensors for respiratory virus detection with the use of nanotechnology. These fabricated sensors demonstrated a number of benefits, including precision, affordability, accessibility, and miniaturization which makes them a promising test method for point-of-care (PoC) screening for SARS-CoV-2 viral infection. In order to comprehend the principles of electrochemical sensing and the role of various types of sensing interfaces, we comprehensively explored the underlying principles of electroanalytical methods and terminologies related to it in this review. In addition, it is addressed how to fabricate electrochemical sensing devices incorporating nanomaterials as graphene, metal/metal oxides, metal organic frameworks (MOFs), MXenes, quantum dots, and polymers. We took an effort to carefully compile current developments, advantages, drawbacks, possible solutions in nanomaterials based electrochemical sensors.

Carbon Paste Electrodes Surface-Modified with Surfactants: Principles of Surface Interactions at the Interface between Two Immiscible Liquid Phases

Carbon paste electrodes ex-situ modified with different surfactants were studied using cyclic voltammetry with two model redox couples, namely hexaammineruthenium (II)/(III) and hexacyanoferrate (II)/(III), in 0.1 mol L-1 acetate buffer (pH 4), 0.1 mol L-1 phosphate buffer (pH 7), and 0.1 mol L-1 ammonia buffer (pH 9) at a scan rate ranging from 50 to 500 mV s-1. Distinct effects of pH, ionic strength, and the composition of supporting media, as well as of the amount of surfactant and its accumulation at the electrode surface, could be observed and found reflected in changes of double-layer capacitance and electrode kinetics. It has been proved that, at the two-phase interface, the presence of surfactants results in elctrostatic interactions that dominate in the transfer of model substances, possibly accompanied also by the effect of erosion at the carbon paste surface. The individual findings depend on the configurations investigated, which are also illustrated on numerous schemes of the actual microstructure at the respective electrode surface. Finally, principal observations and results are highlighted and discussed with respect to the future development and possible applications of sensors based on surfactant-modified composited electrodes.

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.