A novel disposable electrochemical sensor based on modifying graphite pencil lead electrode surface with nanoacetylene black for simultaneous determination of antiandrogens flutamide and cyproterone acetate

Surface engineering of carbon microspheres with nanoceria wrapped on MWCNTs: a dual electrocatalyst for simultaneous monitoring of molnupiravir and paracetamol

In the present study, nanoceria-decorated MWCNTs (CeNPs@MWCNTs) were synthesized using a simple and inexpensive process. Molnupiravir (MPV) has gained considerable attention in recent years due to the infection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Since some people infected with COVID-19 experience fever and headaches, paracetamol (PCM) has been prescribed to relieve these symptoms. Therefore, there is an urgent need to monitor and detect these drugs simultaneously in pharmaceutical and biological samples. In this regard, we developed a novel sensor based on nanoceria-loaded MWCNTs (CeNPs@MWCNTs) for simultaneous monitoring of MPV and PCM. The incorporation of CeNPs@MWCNTs electrocatalyst into a glassy carbon microsphere fluorolube oil paste electrode (GCMFE) creates more active sites, which increase the surface area, electrocatalytic ability, and electron transfer efficiency. Interestingly, CeNPs@MWCNTs modified GCMFE demonstrated excellent detection limits (6.0 nM, 8.6 nM), linear ranges (5.0-5120 nM, 8.0-4162 nM), and sensitivities (78.6, 94.3 μA μM-1 cm-2) for simultaneous detection of MPV and PCM. The developed CeNPs@MWCNTs electrocatalyst modified GCMFE exhibited good repeatability, anti-interference capability, stability, and real-time analysis with good recovery results, which clearly indicates that it can be used for real-time industrial applications.

Electrochemical Detection of Flutamide by the Composite of Complex Based on Thiacalix[4]arene Derivatives and Reduced Graphene Oxide

In this paper, a thiacalix[4]arene complex [Zn2(TIT4A)L2]·4DMF·2CH3OH (H2L = 4,4'-oxybisbenzoic acid) (Zn-TIT4A-L) was synthesized by a solvothermal method. The composites were prepared by combining Zn-TIT4A-L with reduced graphene oxide (RGO), mesoporous carbon (MC), and multi-walled carbon nanotubes (MWCNTs), respectively. Three representative composites are Zn-TIT4A-L@RGO(1:1), Zn-TIT4A-L@MC(1:2), and Zn-TIT4A-L@MWCNT(1:2). X-ray diffraction and scanning electron microscopy characterized their structures and morphologies. The results showed that three composites were successfully prepared, and the crystals of the complex remained in the composites. The electrochemical properties of the composites were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicated that they had good electrocatalytic activity and conductivity. Among them, Zn-TIT4A-L@RGO(1:1) had the best performance and was used for the quantitative detection of flutamide (FTA). The linear range of detection is 0.1-200 μM, and the limit of detection is 0.015 μM. At the same time, the sensor also had good reproducibility, anti-interference, and stability. The sensor was also used for the detection of FTA in lake water, human urine, and serum with a satisfactory recovery rate. The possible mechanism of electrochemical detection of FTA was also discussed.

Synergistic effect of gold nanoparticles anchored on conductive carbon black as an efficient electrochemical sensor for sensitive detection of anti-COVID-19 drug Favipiravir in absence and presence of co-administered drug Paracetamol

Favipiravir (FVP) is introduced as a promising newly developed antiviral drug against the coronavirus disease 2019 (COVID-19). Therefore, the accurate determination of FVP is of great significance for quality assessment and clinical diagnosis. Herein, a novel electrochemical sensing platform for FVP based on gold nanoparticles anchored conductive carbon black (Au@CCB) modified graphite nanopowder flakes paste electrode (GNFPE) was constructed. Morphological and nanostructure properties of Au@CCB have been investigated by TEM, HRTEM, and EDX methods. The morphology and electrochemical properties of Au@CCB/GNFPE were characterized by SEM, cyclic voltammetry (CV), and EIS. The Au@CCB nanostructured modified GNFPE exhibited strong electro-catalytic ability towards the oxidation of FVP. The performance of the fabricated Au@CCB/GNFPE was examined by monitoring FVP concentrations in the absence and presence of co-administered drug paracetamol (PCT) by AdS-SWV. It was demonstrated that the proposed sensor exhibited superior sensitivity, stability, and anti-interference capability for the detection of FVP. The simultaneous determination of a binary mixture containing FVP and the co-administered drug PCT using Au@CCB/GNFPE sensor is reported for the first time. Under optimized conditions, the developed sensor exhibited sensitive voltammetric responses to FVP and PCT with low detection limits of 7.5 nM and 4.3 nM, respectively. The sensing electrode was successfully used to determine FVP and PCT simultaneously in spiked human plasma and pharmaceutical preparations, and the findings were satisfactory. Finally, the fabricated sensor exhibited high sensitivity for simultaneous detection of FVP and PCT in the presence of ascorbic acid in a real sample.

Recent Developments in Voltammetric Analysis of Pharmaceuticals Using Disposable Pencil Graphite Electrodes

The even growing production of both well-known and new derivatives with pharmaceutical action involves the need for developing facile and reliable methods for the analysis of these compounds. Among the widely used instrumental techniques, the electrochemical ones are probably the simplest and the most rapid, also having good performance characteristics. However, the key tool in electroanalysis is the working electrode. Due to the inherent electrochemical and economic advantages of the pencil graphite electrode (PGE), the interest in its applicability in the analysis of different analytes has continuously increased in recent years. Thus, this paper aims to review the scientific reports published in the last 10 years on the use of the disposable eco- and user-friendly PGEs in the electroanalysis of compounds of pharmaceutical importance in different matrices. The PGE characteristics and designs (bare or modified with various types of materials), along with their applications and performance parameters (e.g., linear range, limit of detection, and reproducibility), will be discussed, and their advantages and limitations will be critically emphasized.

A molybdenum disulfide-reduced graphene oxide nanocomposite as an electrochemical sensing platform for detecting cyproterone acetate

Based on the synergistic effect of MoS2 and rGO, a MoS2-rGO nanocomposite film shows a wide linear range and high sensitivity towards cyproterone acetate.

3D, large-area NiCo2O4 microflowers as a highly stable substrate for rapid and trace level detection of flutamide in biofluids via surface-enhanced Raman scattering (SERS)

A one-pot hydrothermal synthesis of three-dimensional (3D), large-area, bimetallic oxide NiCo₂O₄ (NCO) microflowers has been developed as a novel substrate for surface-enhanced Raman scattering (SERS) detection of flutamide in biological fluids. The 3D flower-like morphology of the NCO is observed via FESEM micrographs, while the orthorhombic phase formation is confirmed through XRD spectra. Due to the presence of multiple coordination cations of the 3D NCO microflowers (such as Ni²⁺ and Co²⁺), the high surface area and surface roughness, the NCO-modified indium tin oxide (NCO/ITO) SERS substrate exhibits a linear detection range from 0.5-500 nM with a low limit of detection (LOD) of 0.1 nM. The SERS substrate provides a high enhancement factor of 1.864 × 10⁶ with an accumulation time of 30 s using a laser source of λ = 532 nm, which can be ascribed to the excellent and rapid interaction between the flutamide molecule and the NCO microflower substrate that leads to photoinduced charge transfer (PICT) resonance. The NCO/ITO substrate exhibits excellent homogeneity and high chemical stability. Besides, the substrate displays an excellent selectivity to flutamide molecules in the existence of other metabolites such as urea, ascorbic acid (AA), glucose, NaCl, KCl, CaCl₂, and hydroxyflutamide. The NCO/ITO substrate is successful in the trace-level detection of flutamide in simulated blood serum samples. The strategy outlined here presents a novel strategy for the efficacy of transition metal oxides (TMOs) based electrodes useful for a wide variety of bioanalytical applications.

Nanomolar level detection of non-steroidal antiandrogen drug flutamide based on ZnMn2O4 nanoparticles decorated porous reduced graphene oxide nanocomposite electrode

Flutamide is a non-steroidal antiandrogen drug and widely used in the treatment of prostatic carcinoma. Nevertheless, the excessive intake and improper disposal could affect the living organisms. In this work, we have synthesized a new nanocomposite based on ZnMn₂O₄ nanoparticles and porous reduced graphene oxide nanosheets (ZnMn₂O₄-PGO) for the electrocatalytic detection of flutamide (FLU) drug. The crystallinity and morphological properties of ZnMn₂O₄-PGO composite examined by different characterization techniques such as X-ray diffraction, Raman spectroscopy and so on. The fabricated ZnMn₂O₄-PGO nanocomposite modified electrode exhibited superior electrocatalytic performance to FLU drug in an optimized pH electrolyte. Fascinatingly, the electrode received a wide linear range (0.05-3.5 µM) with limit of detection of 8 nM. Besides, the developed ZnMn₂O₄-PGO nanocomposite electrode showed good sensitivity 1.05 µAµM^-1 cm^-2 and excellent selectivity for FLU detection in presence of various interfering species. A developed disposable electrode was scrutinized to determine FLU level in human urine samples by spiking method and the results achieved good recoveries in real sample analysis.

A molecularly imprinted poly 2-aminophenol-gold nanoparticle-reduced graphene oxide composite for electrochemical determination of flutamide in environmental and biological samples

A selective and sensitive electrochemical sensor based on reduced graphene oxide, gold nanoparticles, and molecularly imprinted poly 2-aminophenol was developed for electrochemical determination of flutamide in environmental and biological samples. The composite fabrication was electrochemically carried out and the composite was characterized by Fourier transform infrared, proton and carbon nuclear magnetic resonance, field emission scanning electron microscopy, and energy-dispersive X-ray spectrometry. The spectroscopic results showed that polymerization of molecularly imprinted poly 2-aminophenol took place through a ladder structure system. After optimization of effective parameters on the response of the sensor, the obtained linear range, relative standard deviation (for a concentration of 50 μg L^-1 with five replicates) and limit of quantification for flutamide determination were determined to be 2-375 μg L^-1, 1.54% and 0.8 μg L^-1, respectively. The results showed that the application of poly 2-aminophenol in the structure of the proposed sensor using a molecular imprinting approach made the sensor highly selective toward flutamide, distinguishing it from similar nitro-containing compounds. The prepared sensor was successfully utilized to analyze environmental water and urine samples. The obtained results showed that the proposed method is in agreement with the HPLC method and can be used as a reliable alternative method for the analysis of flutamide.