Azithromycin-molecularly imprinted polymer based on PVC membrane for Azithromycin determination in drugs using coated graphite electrode

Current Trends in Nanomaterials-Based Electrochemiluminescence Aptasensors for the Determination of Antibiotic Residues in Foodstuffs: A Comprehensive Review

Veterinary pharmaceuticals have been recently recognized as newly emerging environmental contaminants. Indeed, because of their uncontrolled or overused disposal, we are now facing undesirable amounts of these constituents in foodstuff and its related human health concerns. In this context, developing a well-organized environmental and foodstuff screening toward antibiotic levels is of paramount importance to ensure the safety of food products as well as human health. In this case, with the development and progress of electric/photo detecting, nanomaterials, and nucleic acid aptamer technology, their incorporation-driven evolving electrochemiluminescence aptasensing strategy has presented the hopeful potentials in identifying the residual amounts of different antibiotics toward sensitivity, economy, and practicality. In this context, we reviewed the up-to-date development of ECL aptasensors with aptamers as recognition elements and nanomaterials as the active elements for quantitative sensing the residual antibiotics in foodstuff and agriculture-related matrices, dissected the unavoidable challenges, and debated the upcoming prospects.

Highly sensitive electrochemical sensor based on carbon paste electrode modified with graphene nanoribbon-CoFe2O4@NiO and ionic liquid for azithromycin antibiotic monitoring in biological and pharmaceutical samples

In this report, Azithromycin (Azi) antibiotic was measured by carbon paste electrode (CPE) improved by graphene nanoribbon-CoFe2O4@NiO nanocomposite and 1-hexyl-3 methylimidazolium hexafluorophosphate (HMIM PF6) as an ionic liquid binder. The electrochemical behavior of Azi on the graphene nanoribbon-CoFe2O4@NiO/HMIM PF6/CPE is investigated by voltammetric methods, and the results showed that the modifiers improve the conductivity and electrochemical activity of the CPE. According to obtained data, the electrochemical behavior of Azi is related to pH. under optimum conditions, the sensor has linear ranges from 10 µM to 2 mM with a LOD of 0.66 µM. The effect of scan rate and chronoamperometry were studied, which showed that the Azi electro-oxidation is diffusion controlled with the diffusion coefficient of 9.22 × 10-6 cm2/s. The reproducibility (3.15%), repeatability (2.5%), selectivity, and stability (for 30 days) tests were investigated, which results were acceptable. The actual sample analysis confirmed that the proposed sensor is an appropriate electrochemical tool for Azi determination in urine and Azi capsule.

Graphite based sensor amended with fumed silica for electro-detecting Azithromycin

Azithromycin (AM) detection has become of great interest as being one of the prescribed medicines in the medication protocol in Egypt for the recent COVID-19 pandemic. Herein, a carbon paste electrode (CPE) was simply amended with fumed silica (FS) for determining AM. The characterization of the new material was done by different techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS). The newly modified fumed silica carbon paste electrode (FSCPE) exhibited a highly sensitive response towards the oxidation of 1.0 mM AM in phosphate buffer solution (PBS) for a pH range of 5.0 - 10.0. The effect of varying AM concentrations was studied in PBS of pH 7.4 with a detection limit of 11 µM and a quantification limit of 37 µM. Eventually, the recently amended electrode attained reasonable sensitivity and constancy for AM detection in actual trials like blood plasma and pharmaceutical drugs.

Preparation and performance analysis of monodisperse glycidyl methacrylate modified restricted access media-imprinted materials

Using monodisperse poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as the matrix, and pefloxacin template molecules, a novel restricted-access medium molecularly imprinted polymers with Bovine serum albumin crosslinked on its surface was prepared through reversible addition fragmentation chain-transfer polymerization. Then, the obtained material was employed in dispersive solid-phase extraction to analyze the fluoroquinolones in untreated egg samples by HPLC-UV detection. Adsorption performance revealed a good binding amount (40.72 mg/g), fast binding kinetics (25 min), satisfactory selectivity and good ability to eliminate matrix interference. The Reusability experiments indicated the materials has good reusable performance after repeated. Under the optimised conditions, restricted access media-molecularly imprinted polymers-dispersive solid phase extraction was combined with HPLC-UV to enrich fluoroquinolones in untreated eggs, good limit of detection (1.31-3.15 μg/L) and high recovery (89.5%-96.8%) were obtained. The results showed that the prepared restricted-access material is promising for direct detection of antibiotics in complex samples. This article is protected by copyright. All rights reserved.

Molecularly Imprinted Polymer Based GCE for Ultra-sensitive Voltammetric and Potentiometric Bio Sensing of Topiramate

Topiramate (TOP) drug is classified as one of the most commonly used human drugs for anticonvulsants and antiepileptic, so its rapid detection and monitoring is of great importance. In this work, new potentiometric (MIP/PVC/GCE) and voltammetric (MIP/GO/GCE) sensors for the selective and sensitive determination of TOP were fabricated based on the molecularly imprinted polymer (MIP) approach. The MIP was synthesized by the polymerization of acrylamide and methacrylic acid as monomers, in the presence of TOP as a template and ethylene glycol dimethacrylate as a cross-linker. The obtained products were characterized by FT-IR, SEM, BET, and EDX. The MIP was embedded in a plasticized polyvinyl chloride membrane and used as a potentiometric sensor for sensing TOP. Alternatively, the synthesized MIP and graphene oxide (GO) were deposited layer-by-layer on the surface of GCE to construct a voltammetric sensor for studying the electrochemical behavior of the drug. Under optimized conditions, both electrochemical sensors showed excellent linear relationships between the concentration of TOP and the response signals of MIP/GO/GCE or MIP/PVC/GCE sensors in the 2.7 × 10^-10 to 4.9 × 10^-3 M and 1 × 10^-9 to 3.4 × 10^-3 M ranges, respectively. Also, both sensors have good reproducibility and high stability for up to 15 days for a voltammetric sensor and 28 days for a potentiometric sensor. The utility of these sensors was checked for TOP analysis in different real samples with good recovery (92.8 - 99%).

Recent Progress of Imprinted Nanomaterials in Analytical Chemistry

Molecularly imprinted polymers (MIPs) are a type of tailor-made materials that have ability to selectively recognize the target compound/s. MIPs have gained significant research interest in solid-phase extraction, catalysis, and sensor applications due to their unique properties such as low cost, robustness, and high selectivity. In addition, MIPs can be prepared as composite nanomaterials using nanoparticles, multiwalled carbon nanotubes (MWCNTs), nanorods, quantum dots (QDs), graphene, and clays. This review paper aims to demonstrate and highlight the recent progress of the applications of imprinted nanocomposite materials in analytical chemistry.

Imprinting Technology in Electrochemical Biomimetic Sensors

Biosensors are a promising tool offering the possibility of low cost and fast analytical screening in point-of-care diagnostics and for on-site detection in the field. Most biosensors in routine use ensure their selectivity/specificity by including natural receptors as biorecognition element. These materials are however too expensive and hard to obtain for every biochemical molecule of interest in environmental and clinical practice. Molecularly imprinted polymers have emerged through time as an alternative to natural antibodies in biosensors. In theory, these materials are stable and robust, presenting much higher capacity to resist to harsher conditions of pH, temperature, pressure or organic solvents. In addition, these synthetic materials are much cheaper than their natural counterparts while offering equivalent affinity and sensitivity in the molecular recognition of the target analyte. Imprinting technology and biosensors have met quite recently, relying mostly on electrochemical detection and enabling a direct reading of different analytes, while promoting significant advances in various fields of use. Thus, this review encompasses such developments and describes a general overview for building promising biomimetic materials as biorecognition elements in electrochemical sensors. It includes different molecular imprinting strategies such as the choice of polymer material, imprinting methodology and assembly on the transduction platform. Their interface with the most recent nanostructured supports acting as standard conductive materials within electrochemical biomimetic sensors is pointed out.