In situ polymerization and FT-IR characterization of poly-glycine on pencil graphite electrode for sensitive determination of anti-emetic drug, granisetron in injections and human plasma

Electrochemical investigation of an anticancer drug 5-Fluorouracil in the presence of Theophylline using low-cost and disposable poly(GLY) modified pencil graphite electrode

Herein this study, a facile, efficient and disposable electrochemical sensor has been prepared by electropolymerization of glycine (poly(GLY)) on the surface of pencil graphite electrode (PGE). The surface topology of the equipped poly(GLY) modified pencil graphite electrode (poly(GLY)/PGE) and bare pencil graphite electrode (BPGE) has been characterized by the scanning electron microscopy (SEM) combined with energy dispersive x-ray analysis (EDX) and charge transfer behaviour was measured by electron impedance spectroscopy (EIS) method. The voltammetric behaviour of anticancer, 5-fluorouracil (5-FU) in the presence of theophylline (THP) has been carried out in 0.1 M phosphate buffer solution (PBS) of physiological pH 7.0 using different techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). The proposed poly(GLY)/PGE shows augmented peak current for 5-FU at lower potential side over the BPGE due to the electrocatalytic behaviour of modifier layers wrapped on the electrode surface. The kinetic behaviour of 5-FU at modified electrode surface was studied by varying different parameters such as pH, scan rate and concentration study in 0.1 M PBS used as a supporting electrolyte. The limit of detection (LOD) for 5-FU was attained using DPV method with different concentrations (1.0-13.0 μM) and it was found to be 0.012 μM. The possible electrochemical reaction of 5-FU was proposed and it was incorporated by two electrons and two protons mechanism at modified electrode surface. The voltammetric response of poly(GLY)/PGE towards the determination of 5-FU was unaffected in the presence of some excipients in addition to the remarkable stability and reproducibility. The applicability of the proposed sensor has been performed by real sample investigation of 5-FU with a substantial percentage of recovery results in all optimized conditions.

A Facile Glycerol-Assisted Synthesis of Low-Cu2+-Doped CoFe2O4 for Electrochemical Sensing of Acetaminophen

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 Cu0.13Co0.87Fe2O4/GCE corresponds extremely well with its resistance Rct, 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 Cu0.13Co0.87Fe2O4/GCE sensor has outstanding practicability and could be utilized to detect AC content in real complex biological samples.

Sensitive and selective determination of paracetamol in antipyretic children's syrup with a polyglycine modified glassy carbon electrode

A sensitive and selective electrochemical sensor for the determination of paracetamol (acetaminophen) is proposed based on a polyglycine-coated glassy carbon electrode. The electrochemical behavior of paracetamol was studied by cyclic voltammetry and differential pulse voltammetry. Under optimal experimental conditions, the peak oxidation current of paracetamol increases linearly in the range of 0.5-75 μM. The limit of detection of paracetamol was 0.03 μM and the limit of quantitation was 0.09 μM. In addition, modified glassy carbon with polyglycine as the sensor was successfully used for the determination of paracetamol in antipyretic children's syrup samples, with a recovery rate of over 95.3%, showing its great application potential in drug analysis.

Polypyrrole/carbon dot nanocomposite as an electrochemical biosensor for liquid biopsy analysis of tryptophan in the human serum of normal and breast cancer women

Liquid biopsy analysis represents a suitable alternative analysis procedure in several cases where no tumor tissue is available or in poor patient conditions. Amino acids can play a crucial role in aiding cancer diagnosis. Monitoring of tryptophan (Trp) catabolism can aid in tracking cancer progression. Therefore, a novel nanocomposite was fabricated using overoxidized polypyrrole film doped with nano-carbon dots (nano-CDs) on the pencil graphite electrode (PGE) surface for sensitive evaluation of Trp in human serum. Using square wave voltammetry (SWV), the overoxidized polypyrrole/carbon dots/pencil graphite electrode (Ov-Ox PPy/CDs/PGE) achieved excellent electrochemical catalytic activity for evaluating Trp. The modified electrode, known as Ov-Ox PPy/CDs/PGE, demonstrated superior electrochemical catalytic activity compared to bare PGE, CDs/PGE, PPy/PGE, and PPy/CDs/PGE for evaluation of Trp. The method's excellent sensitivity was confirmed by the low limits of detection (LOD = 0.003 μmol L-1) and limit of quantitation (LOQ = 0.009 μmol L-1). The biosensor that was developed can measure tryptophan (Trp) levels in the serum of both healthy individuals and female breast cancer patients with high accuracy and sensitivity. The results indicate that there is a significant difference, as shown by the F-test, between healthy individuals and those with breast cancer. This suggests that Trp amino acid could be an essential biomarker for cancer diagnosis. Consequently, liquid biopsy analysis presents a valuable opportunity for early disease detection, particularly for cancer.

An Innovative Polymer-Based Electrochemical Sensor Encrusted with Tb Nanoparticles for the Detection of Favipiravir: A Potential Antiviral Drug for the Treatment of COVID-19

An innovative polymer-based electro-sensor decorated with Tb nanoparticles has been developed for the first time. The fabricated sensor was utilized for trace determination of favipiravir (FAV), a recently US FDA-approved antiviral drug for the treatment of COVID-19. Different techniques, including ultraviolet-visible spectrophotometry (UV-VIS), cyclic voltammetry (CV), scanning electron microscope (SEM), X-ray Diffraction (XRD) and electrochemical impedance spectroscopy (EIS), were applied for the characterization of the developed electrode TbNPs@ poly m-THB/PGE. Various experimental variables, including pH, potential range, polymer concentration, number of cycles, scan rate and deposition time, were optimized. Moreover, different voltammetric parameters were examined and optimized. The presented SWV method showed linearity over the range of 10-150 × 10-9 M with a good correlation coefficient (R = 0.9994), and the detection limit (LOD) reached 3.1 × 10-9 M. The proposed method was applied for the quantification of FAV in tablet dosage forms and in human plasma without any interference from complex matrices, obtaining good % recovery results (98.58-101.93%).

Transition Metal Substituted Barium Hexaferrite-Modified Electrode: Application as Electrochemical Sensor of Acetaminophen

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 Ba1.0Co1.22Fe11.41O18.11 GCE, (0.577 ± 0.007) µM for the Ba1.14Cu0.82Fe11.65O18.02 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 (CoFM) and Copper-substituted barium hexaferrites (CuFM), respectively. These results confirm the high electrochemical activity of Ba1.0Co1.22Fe11.41O18.11 nanoparticles and thus their potential for use in the development of sensing devices for substances of pharmaceutical interest, such as acetaminophen (NAP).