Graphene paste electrode for detection of chlorpromazine

Analytical Performance of Clay Paste Electrode and Graphene Paste Electrode-Comparative Study

The analytical performance of the clay paste electrode and graphene paste electrode was compared using square wave voltammetry (SWV) and cyclic voltammetry (CV). The comparison was made on the basis of a paracetamol (PA) determination on both working electrodes. The influence of pH and SWV parameters was investigated. The linear concentration ranges were found to be 6.0 × 10^-7-3.0 × 10^-5 and 2.0 × 10^-6-8.0 × 10^-5 mol L^-1 for clay paste electrode (ClPE) and graphene paste electrode (GrPE), respectively. The detection and quantification limits were calculated as 1.4 × 10^-7 and 4.7 ×10^-7 mol L^-1 for ClPE and 3.7 × 10^-7 and 1.2 × 10^-6 mol L^-1 for GrPE, respectively. Developed methods were successfully applied to pharmaceutical formulations analyses. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to characterize ClPE and GrPE surfaces. Clay composition was examined with wavelength dispersive X-ray (WDXRF).

A photochemical approach to anchor Au NPs on MXene as a prominent SERS substrate for ultrasensitive detection of chlorpromazine

As a novel two-dimensional (2D) material, metal carbide (MXene) has been identified as a hotspot research topic in the field of surface-enhanced Raman spectroscopy (SERS). Herein, we report the increment of SERS activity of titanium carbide (TiC) by incorporation of gold nanoparticles (Au NPs) by a facile photoreduction process for the detection of antipsychotic drug. TiC anchored with Au NPs produce a remarkable SERS enhancement by the synergistic action of chemical and electromagnetic mechanisms. The hotspots are formed in the nanometer-scale gaps between Au NPs on the TiC surface for the effective interaction with probe molecules. The proposed TiC/Au-NPs SERS substrate was employed for the detection of chlorpromazine (CPZ) with the wide linear range of 10^-1-10^-10 M and the ultra-low limit of detection of 3.92 × 10^-11 M. Besides, the SERS effect of the optimized TiC/Au-NPs for the 532 nm excitation exhibits the enhancement factor in the order of 10⁹ with the relative standard deviation of < 13% for the uniformity and < 8.80% for the reproducibility. To ensure the practical feasibility of the proposed TiC/Au-NPs SERS substrate, the spike and recovery method was used for the detection of CPZ in human biological fluids like urine and saliva. This work can open up a new approach to improve the SERS activity of MXene-based SERS substrate for practical applications, especially the determination of antipsychotic drugs in environmental pollution management.

Rapid electrochemical recognition of trimethoprim in human urine samples using new modified electrodes (CPE/Ag/Au NPs) analysing tunable electrode properties: experimental and theoretical studies

Pharmaceutical effluents are a serious environmental issue, which require to be treated by a suitable technique; thus, the electrochemical process is actively considered as a viable method for the treatment. In this work, new carbon paste electrodes (CPEs) were fabricated by compressing gold and silver nanoparticles (NPs), namely, CPE/Ag NPs, CPE/Au NPs, and CPE/Ag/Au NPs and then completely characterized by different analytical methods. The performance of the electrodes was studied after determining their surface area (×10^-6 cm²) as 4.17, 5.05, 5.27, and 5.12, producing high anodic currents for K₄[Fe(CN)₆] compared to the commercial electrode. This agrees with the results of impedance study, where the electron transfer rate constants (k_app, ×10^-3 cm s^-1) were determined to be 28.7, 42.6, 41.0, and 101.4 for CPE, CPE/Ag NPs, CPE/Au NPs, and CPE/Ag/Au NPs, respectively, through the Bode plot-phase shifts. This is consistent with the charge transfer resistance (R_CT, Ω), resulting as 171 for CPE/Ag/Au NPs < 395 for CPE/Ag NPs < 427 for CPE/Au NPs and < 742 for CPE. Therefore, these electrodes were employed to detect trimethoprim (TMP) since metallic NPs contribute good crystallinity, stability, conduciveness, and surface plasmon resonance to the CPE, convalescing the sensitivity; comprehensively, they were applied for its detection in real water and human urine samples, and the limit of detection (LOD) was as low as 0.026, 0.032, and 0.026 μmol L^-1 for CPE/Ag NPs, CPE/Au NPs, and CPE/Ag/Au NPs, respectively. In contrast, unmodified CPE was unable to detect TMP due to the lack of efficiency. The developed technique shows excellent electrochemical recovery of 92.3 and 97.1% in the urine sample. Density functional theory (DFT) was used to explain the impact of the metallic center in graphite through density of states (DOS).

Sonochemical synthesis of iron-graphene oxide/honeycomb-like ZnO ternary nanohybrids for sensitive electrochemical detection of antipsychotic drug chlorpromazine

We report a novel electrochemical sensor for the sensitive and selective determination of the antipsychotic drug chlorpromazine (CPZ) based on the iron (Fe) nanoparticles-loaded graphene oxide (GO-Fe)/three dimensional (3D) honeycomb-like zinc oxide (ZnO) nanohybrid modified screen printed carbon electrode (SPCE). The 3D hierarchical honeycomb-like ZnO was synthesized using a novel aqueous hydrothermal method and the GO-Fe/ZnO nanohybrid was prepared based on an inexpensive and fast sonochemical method using a high-intensity ultrasonic bath (Delta DC200H, 200 W, 40 KHz). Characterizations including scanning electron microscopy, elemental mapping, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy were carried out as part of this work. The electrocatalytic oxidation behavior of CPZ at various electrodes was investigated using the cyclic voltammetry technique, through which the GO-Fe/ZnO modified SPCE was identified as the best performing electrode. The quantitative determination of CPZ was then performed using the differential pulse voltammetry technique. The as-prepared GO-Fe/ZnO/SPCE sensor exhibited a quick and sensitive response towards the oxidation of CPZ with linear concentration ranges from 0.02 to 172.74 μM and 222.48 to 1047.74 μM. The modified SPCE sensor displayed a low detection limit (LOD) of 0.02 µM and a high sensitivity of 7.56 µA µM^-1 cm^-2. The proposed sensor also showed remarkable operational and storage stability, reproducibility, and repeatability. Furthermore, the practicability of the GO-Fe/ZnO/SPCE sensor has been verified with real sample analysis using commercial antipsychotic CPZ tablets and human urine samples, and adequate recovery has been achieved.

Phenothiazine-Based Organic Catholyte for High-Capacity and Long-Life Aqueous Redox Flow Batteries

Redox-active organic materials have been considered as one of the most promising "green" candidates for aqueous redox flow batteries (RFBs) due to the natural abundance, structural diversity, and high tailorability. However, many reported organic molecules are employed in the anode, and molecules with highly reversible capacity for the cathode are limited. Here, a class of heteroaromatic phenothiazine derivatives is reported as promising positive materials for aqueous RFBs. Among these derivatives, methylene blue (MB) possesses high reversibility with extremely fast redox kinetics (electron-transfer rate constant of 0.32 cm s^-1 ), excellent stability in both neutral and reduced states, and high solubility in an acetic-acid-water solvent, leading to a high reversible capacity of ≈71 Ah L^-1 . Symmetric RFBs based on MB electrolyte demonstrate remarkable stability with no capacity decay over 1200 cycles. Even concentrated MB catholyte (1.5 m) is still able to deliver stable capacity over hundreds of cycles in a full cell system. The impressive cell performance validates the practicability of MB for large-scale electrical energy storage.

Electrochemical Analysis of Antipsychotics

Introduction:

Schizophrenia is seizures accompanied by severe psychotic symptoms, and a steady state of continuation in the form of periods of stagnation. Antipsychotics are now the basis of treatment for schizophrenia and there is no other molecule that is antipsychotic priority in treatment. Antipsychotics can be classified into two groups; dopamine receptor antagonists such as promazine, fluphenazine etc. and serotonin-dopamine antagonists including risperidone, olanzapine, ziprasidone, aripiprazole etc.

Materials and Methods:

Electrochemical methods have been used for the determination of antipsychotic agent just as used in the determination of many drug agents. Nearly all of the antipsychotics are electroactive and can be analyzed by electrochemical methods. Electroanalytical methods offer generally high sensitivity, are compatible with modern techniques, have low cost, low requirements, and compact design. Among the most commonly used types, there are cyclic voltammetry, differential pulse voltammetry, square wave voltammetry and linear sweep voltammetry.

Conclusion:

The aim of this review is to evaluate the main line and the advantages and uses of electroanalytical methods that employed for the determination of antipsychotic medication agents used in schizophrenia. Moreover, applications of the methods to pharmaceutical analysis of Antipsychotics upto- date is also summarized in a table.

Functionalization of a carbon nanofiber with a tetrasulfonatophenyl ruthenium(II)porphine complex for real-time amperometric sensing of chlorpromazine

A carbon nanofiber functionalized with ruthenium(II)-tetrasulfonato phenyl porphine (CNF/Ru-TSPP) is shown to be viable sensor for amperometric determination of the antipsychotic drug chlorpromazine (CPZ). The hollow platelet structured Ru-TSPP combines with the hollow cylindrical tube-like structure of the CNF via π stacking interaction. The morphological and electro conductive properties of the electrode were characterized by spectrophotometric techniques. The CNF/Ru-TSPP modified electrode displays a large surface-to-volume ratio, good electron transport and good electrocatalytic activity. The amperometric sensor, typically operated at a potential 0.63 V (vs. Ag/AgCl) exhibits a linear response in the 0.6 nM to 1.1 mM CPZ concentration range, has a 0.2 nM detection limit, and a remarkably good electrochemical sensitivity (2.405 μA μM^-1 cm^-2). The sensor is selective, repeatable and reproducible. It was successfully applied to the determination of CPZ in spiked serum samples. Graphical abstract Schematic presentation of carbon nanofiber/ tetrasulfonatophenyl Ruthenium(II)porphine (CNF/Ru-TSPP) nanocomposite synthesis and application for the electrochemical determination of chlorpromazine (CPZ).

Exploring the electrochemical performance of graphite and graphene paste electrodes composed of varying lateral flake sizes

We report the fabrication, characterisation (SEM/EDX, TEM, XRD, XPS and Raman spectroscopy) and electrochemical properties of graphite and graphene paste electrodes with varying lateral flake sizes. The fabricated paste electrodes are electrochemically analysed using both outer-sphere and inner-sphere redox probes, namely; hexaammineruthenium(iii) chloride, N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), potassium ferrocyanide(ii) and ammonium ferrous(ii) sulphate. Upon comparison of different graphite paste electrodes, a clear correlation between the lateral flake sizes (La), ranging from 1.5 mm-0.5 μm, and electrochemical activity (heterogeneous electron transfer (HET) kinetics) is evident, where an improvement in the HET is observed at smaller lateral flake sizes. We infer that the beneficial response evident when employing laterally smaller flakes is due to an increased number of edge plane like-sites/defects available upon the electrode surface, facilitating electron transfer. Interestingly, given that the overall lateral flake sizes of the graphenes utilised (10.0-1.3 μm) were significantly smaller than those studied previously, an improvement in HET kinetics was also evident with the reduction of lateral flake size; the extent to which is redox-probe dependent. Improvements are observed up to a distinct point, termed the 'lateral size threshold' (ca. ≤2 μm) where the electrochemical reversible limit is approached. Further support is provided from density functional theory (DFT), exploring the electronic structure (i.e. HOMO-LUMO) as a function of flake size, which demonstrates that the coverage of edge plane like-sites/defects comprising the geometric structure of the relatively small graphene flakes is such that effectively the entire flake has become electrochemically active. In this study, the importance of lateral flake size with respect to electrochemical reactivity at carbon-based electrodes has been demonstrated alongside a structural relationship upon HET performance, a phenomenon that has not previously been described in the literature. Such work is both highly important and informative for the field of electrochemistry and electrode performance, with potential implications in a plethora of areas, ranging from novel renewable energy sources to electroanalytical sensing platforms.

Synthesis and characterization of the thermally reduced graphene oxide in argon atmosphere, and its application to construct graphene paste electrode as a naptalam electrochemical sensor

New insight into the preparation of sensitive carbon-based electrochemical electrode is provided by examining the properties of thermally reduced graphene oxide (TRGO). In this paper, TRGO was prepared by thermal reduction of graphene oxide (GO) in argon atmosphere, and characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and atomic force microscopy (AFM). Results showed that thermal reduction in argon was effective to remove oxygen-containing functional groups in GO, and graphene sheets were obtained. Furthermore, TRGO was used to prepare thermally reduced graphene oxide paste electrode (TRGOPE) which showed excellent conductivity and fast electron transfer kinetics confirmed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrode was applied to determination of the pesticide naptalam (Nap) in square-wave voltammetric (SWV) mode. The corresponding current at approx. +1.0 V increased linearly with the Nap concentration within two linear dynamic ranges (LDR) of 0.1-1.0 μmol L^-1 (LDR₁) and 1.0-10.0 μmol L^-1 (LDR₂). The limits of detection (LOD) and quantification (LOQ) for Nap were calculated as 0.015 μmol L^-1 and 0.051 μmol L^-1, respectively. In comparison to the carbon paste electrode (CPE) the results showed that the TRGOPE possesses advantages in terms of linearity, sensitivity and detectability.

One-step sonochemical synthesis of 1D β-stannous tungstate nanorods: An efficient and excellent electrocatalyst for the selective electrochemical detection of antipsychotic drug chlorpromazine

In the modern world, the contamination of ecosystem by human and veterinary pharmaceutical drugs through the metabolic excretion, improper disposal/industrial waste has been subjected to a hot issue. Therefore, exploitation of exclusive structured material and reliable technique is a necessary task to the precise detection of drugs. With this regards, we made an effort for the fabrication of novel one-dimensional (1D) stannous tungstate nanorods (β-SnW NRs) via simple sonochemical approach and used as an electrochemical sensor for the detection of antipsychotic drug chlorpromazine (CPZ) for the first time. The crystallographic structure, surface topology, elemental compositions and their distributions and ionic states were enquired by different spectroscopic techniques such as XRD, FTIR, SEM, EDS, elemental mapping and XPS analysis. The developed β-SnW NRs/GCE sensor exhibits a rapid and sensitive electrochemical response towards CPZ sensing with wide linear response range (0.01-457 µM), high sensitivity (2.487 µA µM^-1 cm^-2), low detection limit (0.003 µM) and excellent selectivity. Besides, the as-proposed electrochemical sensor was successfully applied to real sample analysis in commercial CPZ drug and biological fluids and the acquired recovery results are quite satisfactory. The proposed sonochemical method for the preparation of β-SnW NRs is low cost, very simple, fast and efficient for sensor applications.

Highly selective electrochemical detection of antipsychotic drug chlorpromazine in drug and human urine samples based on peas-like strontium molybdate as an electrocatalyst

Electrochemical detection of antipsychotic drug chlorpromazine based on peas-like strontium molybdate as an electrocatalyst.

A Facile Electrochemical Preparation of Reduced Graphene Oxide@Polydopamine Composite: A Novel Electrochemical Sensing Platform for Amperometric Detection of Chlorpromazine

We report a novel and sensitive amperometric sensor for chlorpromazine (CPZ) based on reduced graphene oxide (RGO) and polydopamine (PDA) composite modified glassy carbon electrode. The RGO@PDA composite was prepared by electrochemical reduction of graphene oxide (GO) with PDA. The RGO@PDA composite modified electrode shows an excellent electro-oxidation behavior to CPZ when compared with other modified electrodes such as GO, RGO and GO@PDA. Amperometric i-t method was used for the determination of CPZ. Amperometry result shows that the RGO@PDA composite detects CPZ in a linear range from 0.03 to 967.6 μM. The sensor exhibits a low detection limit of 0.0018 μM with the analytical sensitivity of 3.63 ± 0.3 μAμM^–1cm^–2. The RGO@PDA composite shows its high selectivity towards CPZ in the presence of potentially interfering drugs such as metronidazole, phenobarbital, chlorpheniramine maleate, pyridoxine and riboflavin. In addition, the fabricated RGO@PDA modified electrode showed an appropriate recovery towards CPZ in the pharmaceutical tablets.

Carbon Nanomaterials in Electrochemical Detection

This chapter overviews the use of carbon nanomaterials in the field of electroanalysis and considers why carbon-based nanomaterials are widely utilized and explores the current diverse range that is available to the practising electrochemist, which spans from carbon nanotubes to carbon nanohorns through to the recent significant attention given to graphene.

A novel solid-state electrochemiluminescence sensor based on a Ru(bpy)32+/nano Sm2O3 modified carbon paste electrode for the determination of l-proline

A novel solid-state electrochemiluminescence (ECL) sensor was successfully developed for the determination of l-proline.

Screen-printed resistive pressure sensors containing graphene nanoplatelets and carbon nanotubes

Polymer composites with nanomaterials such as graphene nanoplatelets and carbon nanotubes are a new group of materials with high application possibilities in printed and flexible electronics. In this study such carbon nanomaterials were used as a conductive phase in polymer composites. Pastes with dispersed nanomaterials in PMMA and PVDF vehicles were screen printed on flexible substrates, and used as an active layer in pressure sensors, exploiting contact resistance phenomena. The relationship between resistance and pressure is nearly linear on a logarithmic scale for selected types of samples, and their response is several times higher than for similar sensors with graphite layers. The use of surfactants allowed us to fabricate evenly dispersed nanomaterials with different amount of nanoplatelets and nanotubes in the composites. The samples contained from 1.25 wt.% to 2 wt.% of graphene and 1 wt.% to 0.5 wt.% of nanotubes and exhibited diverse sheet resistivity. Experiments revealed the relationship between morphology and loading of functional phase in the polymer matrix and the sensors' sensitivity.

[Simultaneous determination of chlorpromazine and promethazine and their main metabolites by capillary electrophoresis with electrochemiluminescence]

Based on the phenomenon that each of chlorpromazine (CPZ), promethazine (PMZ), chlorpromazine sulfoxide (CPZSO) and promethazine sulfoxide (PMZSO) could enhance the electrochemiluminescence (ECL) intensity of tris(2,2'-bipyridyl) ruthenium, a novel and sensitive method was proposed for the simultaneous determination of CPZ, PMZ and their main metabolites using capillary electrophoresis (CE) coupled with ECL detection. The influences of several experimental parameters were explored. The optimum experimental conditions were as follows: detection potential of 1. 20 V (Ag/AgCl), 40 mmol/L of phosphate buffer solution (pH 6.5) containing 5 mmol/L tris(2,2'-bipyridyl) ruthenium in ECL detection cell, running buffer solution of 18 mmol/L (pH 4.8), sample injection of 8 s at 11 kV, and separation voltage of 13.5 kV. The detection limits (3sigma) of this method were 8.3 x 10(-7) g/L for CPZ, 7.2 x 10(-6) g/L for PMZ, 1.9 x 10(-5) g/L for CPZSO and 3.7 x 10(-6) g/L for PMZSO. The linear ranges of ECL intensity versus mass concentration of medicaments were 7. 1 x 10(-6) - 6. 3 x 10(-3) g/L for CPZ, 7.5 x 10(-5) - 4.6 x 10(-3) g/L for PMZ, 9.7 x 10(-5) - 3.6 x 10(-3) g/L for CPZSO and 8.1 x 10(-5) - 7.7 x 10(-3) g/L for PMZSO. The relative standard deviations (RSDs) of the four target compounds were not more than 3% for ECL intensity and 1% for migration time. This method has the merits of simplicity, speediness, sensitivity, small sample injection, and free from interference. This method was successfully utilized to directly and simultaneously detect CPZ, PMZ, CPZSO and PMZSO in urine samples of pet dogs.