Facile stripping voltammetric determination of haloperidol using a high performance magnetite/carbon nanotube paste electrode in pharmaceutical and biological samples

Selective and ultrasensitive citric acid assay in urine samples using a MWCNT/Fe3O4 nanoparticle-modified carbon paste electrode

A carbon paste electrode (CPE) modified with multiwalled carbon nanotubes and magnetite nanoparticles is introduced (CNT/Fe₃O₄-CPE) as the most sensitive citric acid (CA) electrochemical sensor reported so far. The structural and spectroscopic characterization by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy is presented. The electrocatalytic performance of the electrode was substantiated using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Performing voltammetric experiments at different pH values and various scan rates gave some evidence for the electro-oxidation mechanism of CA. The EIS study gave an obvious indication for the enhancement of the charge transfer rate of CA by the nanocomposite. Various parameters affecting the electrode performance were studied. Using differential pulse voltammetry it was found that the CNT/Fe₃O₄-CPE showed a linear dynamic range of 5.0 × 10^-7-1 × 10^-4 mol L^-1, an excellent sensitivity of 5184 μA mM^-1 cm^-2, and a detection limit of 3.6 × 10^-7 mol L^-1 for CA determination. The relative standard deviation was found to be 3.1% (n = 3). The method was utilized for CA determination in urine samples without utilizing complicated sample pretreatment.

PVP-coated silver nanocubes as RRS probe for sensitive determination of Haloperidol in real samples

Polyol synthesis of silver nanocubes (Ag NCs) under dark conditions yielded nanoparticles with high uniformity and purity, as well as edge lengths of 42 nm with good stability and scattering cross-section. These nanoparticles were characterized by SEM, TEM, and Uv-vis spectroscopy. The presence of polyvinylpyrrolidone (PVP) as a capping agent on the surface of Ag NCs, as well as its satisfactory interaction level with Haloperidol (Hp) as an antipsychotic drug, has led to the use of these nanoparticles as Resonance RayleighScattering (RRS) probe to measure Hp. Indeed, Hp resulted in reducing the RRS signal of Ag NCs, and this change in RRS intensity was linear in the range of 10.0 to 800.0 µg L^-1 of Hp. The limits of detection (LOD) and quantification (LOQ) were found to be 1.5 and 5.0 µg L^-1, respectively. The influence of interfering species was studied, and it was found that the suggested method has good selectivity and can be used to monitor Hp in actual samples. As a result, this RRS probe operated well in determining Hp in pharmaceutical and human plasma samples with satisfactory recovery.

Chemometrics-assisted Spectrophotometric Method for Simultaneous Estimation of Antipsychotic Drugs in Biological Fluid

Background:

Haloperidol (HP) and Risperidone (RIS) are antipsychotic drugs and the simultaneous determination of these drugs is important. Estimation of HP and RIS alone or in combination with other drugs has been performed in a variety of ways.

Objective:

The aim of this paper was to propose a rapid, simple, accurate, and robust method for the simultaneous determination of HP and RIS using Artificial Neural Networks (ANNs), Partial Least Squares (PLS), and Principal Component Regression (PCR) methods along with spectrophotometry technique.

Methods:

The simultaneous spectrophotometric determination of HP and RIS in synthetic mixtures and biological fluid was performed by applying ANNs Containing Feed-forward Backpropagation (FFBP) and Radial Basis Function (RBF) networks as intelligent methods, as well as PLS, and principal component regression PCR as multivariate calibration methods. The Levenberg- Marquardt (LM), Scaled Conjugate Gradient (SCG), and Resilient Back-propagation (RP) algorithms with different layers and neurons were used in FFBP network and obtained results were compared with each other.

Results:

Among various algorithms of the FFBP network, the LM algorithm was selected as the best model with a lower Mean Square Error (MSE). MSE of the RBF model was 1.46×10-25 and 1.62×10-23 for HP and RIS, respectively. On the other hand, the mean recovery of PLS and PCR was 99.91%, 100.01% and 98.60%, 101.90% for HP and RIS, respectively.

Conclusion:

The proposed models and High-Performance Liquid Chromatography (HPLC) as a reference method were compared with each other by one-way Analysis of Variance (ANOVA) test at the 95 % confidence level for the urine sample. It was observed that the developed methods presented comparable results for the simultaneous determination of HP and RIS.

Simultaneous voltammetric determination of epinephrine and acetaminophen using a highly sensitive CoAl-OOH/reduced graphene oxide sensor in pharmaceutical samples and biological fluids

For this study, three novel types of sensors comprised of CoAl-layered double oxyhydroxide (CoAl-LDH), CoAl-LDH/reduced graphene oxide (rGO), and CoAl-OOH/rGO nanosheets were successfully fabricated on glassy carbon electrodes (GCEs) and employed for the electrochemical detection of epinephrine (EP) and acetaminophen (AC). Interestingly, we found that the CoAl-OOH/rGO/GCE was more suitable for the determination of EP and AC in contrast to the CoAl-LDH and CoAl-OOH/rGO sensors. Differential pulse voltammetry results revealed that the CoAl-OOH/rGO/GCE delivered excellent electrocatalytic activity. The sensitivities and detection limits for the simultaneous measurement of EP and AC were 12.2 μA μM^-1 cm^-2, 0.023 μM L^-1, and 4.87 μA μM^-1 cm^-2, 0.058 μM L^-1, respectively. Especially, the as-obtained CoAl-OOH/rGO/GCE was successfully utilized for the detection in pharmaceutical samples and biological fluids with satisfactory results. Owing to its outstanding electrocatalytic activity and superior sensitivity, the CoAl-OOH/rGO/GCE could be beneficial to construct a promising electrochemical sensor for the detection of EP and AC.

An electrochemical sensor based on chitosan capped with gold nanoparticles combined with a voltammetric electronic tongue for quantitative aspirin detection in human physiological fluids and tablets

Inflammatory diseases increase has recently sparked the research interest for drugs diagnostic tools development. At therapeutic doses, acetylsalicylic acid (ASA or aspirin) is widely used for these diseases' treatment. ASA overdoses can however give rise to adverse side effects including ulcers, gastric damage. Hence, development of simple, portable and sensitive methods for ASA detection is desirable. This paper reports aspirin analysis in urine, saliva and pharmaceutical tablet using an electrochemical sensor and a voltammetric electronic tongue (VE-Tongue). The electrochemical sensor was fabricated by self-assembling chitosan capped with gold nanoparticles (Cs + AuNPs) on a screen-printed carbon electrode (SPCE). It exhibits a logarithmic-linear relationship between its response and the ASA concentration in the range between 1 pg/mL and 1 μg/mL. A low detection limit (0.03 pg/mL), good selectivity against phenol and benzoic acid interference, and successful practical application were demonstrated. Qualitative analysis was performed using the VE-Tongue based unmodified metal electrodes combined with two chemometric approaches to classify urine samples spiked with different aspirin concentrations. Partial least squares (PLS) method provided prediction models obtained from the data of both devices with a regression correlation coefficient R² = 0.99. Correspondingly, the SPCE/(Cs + AuNPs) electrochemical sensor and VE-Tongue could be viable tools for biological analysis of drugs.

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.

Highly sensitive and selective method for the rapid determination and preconcentration of haloperidol by using a magnetite-molecularly imprinted polymer

A sensitive and selective method based on the determination of haloperidol with the usage of magnetite-molecularly imprinted polymer and high-resolution liquid chromatography has been developed. This novel method is rapid as the detection procedure for haloperidol can be completed within a total time of 1 h. The same imprinted polymer can be used for the determination of haloperidol at least 20 times. The proposed method has been succesfully applied to synthetic urine and serum samples and the recoveries of the spiked samples were in the range of 94.7-100.7%. The limit of detection and limit of quantification of the method were 2.25 and 7.50 μg/L, respectively. Linearity of the calibration graph was observed within the range of 10-250 μg/L. By combining the high capacity, high selectivity, and reusability of the magnetic adsorbent with the dynamic calibration range, high sensitivity and high resolution of liquid chromatography with quadrupole time-of-flight mass spectrometry, the proposed method is an ideal method for the determination and preconcentration of trace levels of haloperidol. A magnetite-molecularly imprinted polymer has been used for the first time as a selective adsorbent for the determination of haloperidol.

Graphene nanoribbon/FePt bimetallic nanoparticles/uric acid as a novel magnetic sensing layer of screen printed electrode for sensitive determination of ampyra

A novel electrochemical sensor for sensitive determination of ampyra (Am) based on graphene nanoribbons modified by iron-platinum bimetallic nanoparticles and uric acid (SPCE/FePtGNR/UA) dropped on the screen-printed carbon electrode (SPCE) surface and magnetically captured onto an SPCE working electrode surface is reported in the present work. The modified nanocomposite and sensing layer was characterized by different techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray powdered diffraction (XRD). Am determination by conventional electrochemical methods is not possible, because of its high redox overpotential. Therefore, the differential pulse voltammetry (DPV) signals of UA were used as a redox probe for indirect electrochemical determination of Am. The limit of detection (LOD) and linear concentration range were obtained as 0.028 and 0.08-9.0µmolL^-1 (3S_b/m = 3), respectively. The feasibility of the proposed method was examined by the detection of Am in biological and pharmaceutical samples with satisfactory results. The constructed electrochemical sensor was applied for fast, simple and sensitive detection of Am in real environments.

Modified fractal iron oxide magnetic nanostructure: A novel and high performance platform for redox protein immobilization, direct electrochemistry and bioelectrocatalysis application

A novel biosensing platform based on fractal-pattern of iron oxides magnetic nanostructures (FIOMNs) and mixed hemi/ad-micelle of sodium dodecyl sulfate (SDS) was designed for the magnetic immobilization of hemoglobin (Hb) at a screen printed carbon electrode (SPCE). The FIOMNs was successfully synthesized through hydrothermal approach and characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). In order to provide guidelines for the mixed hemi/ad-micelle formation, zeta-potential isotherms were investigated. The construction steps of the biosensor were evaluated by electrochemical impedance spectroscopy, cyclic voltammetry and Fourier transform infrared spectroscopy. Direct electron transfer of Hb incorporated into the biocomposite film was realized with a pair of quasi-reversible redox peak at the formal potential of -0.355V vs. Ag/AgCl attributing to heme Fe(III)/Fe(II) redox couple. The results suggested that synergistic functions regarding to the hyper-branched and multidirectional structure of FIOMNs and the dual interaction ability of mixed hemi/ad-micelle array of SDS molecules not only induce an effective electron transfer between the Hb and the underlying electrode (high heterogeneous electron transfer rate constant of 2.08s(-1)) but also provide powerful and special microenvironment for the adsorption of the redox proteins. Furthermore, the biosensor displayed an excellent performance to the electrocatalytic reduction of H2O2 with a detection limit of 0.48µM and Michaelis-Menten constant (Km) value of 44.2µM. The fabricated biosensor represented the features of sensitivity, disposable design, low sample volume, rapid and simple preparation step, and acceptable anti-interferences, which offer great perspectives for the screen-determination of H2O2 in real samples.

Sensitive and simple simultaneous determination of morphine and codeine using a Zn2SnO4nanoparticle/graphene composite modified electrochemical sensor

Simultaneous determination of morphine and codeine using a nanocomposite modified electrochemical sensor.

Simultaneous electrochemical sensing of thallium, lead and mercury using a novel ionic liquid/graphene modified electrode

In the present manuscript, an electrochemical sensor for the sensitive detection of Tl(+), Pb(2+) and Hg(2+) is described. A new composite electrode has been fabricated using graphene, 1-n-octylpyridinum hexafluorophosphate (OPFP), and [2,4-Cl2C6H3C(O)CHPPh3] (L), as a new synthetic phosphorus ylide. The physicochemical and electrochemical characterizations of fabricated sensor were investigated in details. The advantages of the proposed composite electrode are its ability in simultaneous electrochemical detection of Tl(+), Pb(2+) and Hg(2+) with good selectivity, stability and no need for separating of the three species from complex mixtures prior to electrochemical measurements. The analytical performance of the proposed electrode was examined using square wave voltammetry. Tl(+), Pb(2+) and Hg(2+) can be determined in linear ranges from 1.25×10(-9) to 2.00×10(-7) mol L(-1). Low detection limits of 3.57×10(-10) mol L(-1) for Tl(+), 4.50×10(-10) mol L(-1) for Pb(2+) and 3.86×10(-10) mol L(-1) for Hg(2+) were achieved. Finally, the proposed electrochemical sensor was applied to detect trace analyte ions in various water and soil samples with satisfactory results.

Simultaneous and sensitive determination of melatonin and dopamine with Fe3O4 nanoparticle-decorated reduced graphene oxide modified electrode

An electrochemical sensor based on a new nanocomposite of graphene/Fe₃O₄ has been fabricated for simultaneous determination of melatonin and dopamine.

A new electrochemical sensor based on a nitrogen-doped graphene/CuCo2O4 nanocomposite for simultaneous determination of dopamine, melatonin and tryptophan

An electrochemical sensor was fabricated for the simultaneous determination of dopamine, melatonin and tryptophan in biological and pharmaceutical samples.

A novel sensor for sensitive determination of atropine based on a Co3O4-reduced graphene oxide modified carbon paste electrode

Co₃O₄-reduced graphene oxide acted as a selective and sensitive modifier in a sensing layer for electrochemical determination of atropine.

Improvement in the performance of a zinc ion-selective potentiometric sensor using modified core/shell Fe3O4@SiO2nanoparticles

A novel, simple, accurate and sensitive zinc ion-selective potentiometric sensor was fabricated by modifying the surface of Fe₃O₄@SiO₂nanoparticles using a ligand prepared by a coupled reaction between APTMS and 2-H-3-MBA.

Simultaneous electrochemical determination of acetaminophen, caffeine and ascorbic acid using a new electrochemical sensor based on CuO–graphene nanocomposite

A sensor using CuO nanoparticles and graphene was constructed. It is a useful tool for determining of acetaminophen, caffeine and ascorbic acid.

Optimization of modified carbon paste electrode with multiwalled carbon nanotube/ionic liquid/cauliflower-like gold nanostructures for simultaneous determination of ascorbic acid, dopamine and uric acid

We describe the modification of a carbon paste electrode (CPE) with multiwalled carbon nanotubes (MWCNTs) and an ionic liquid (IL). Electrochemical studies by using a D-optimal mixture design in Design-Expert software revealed an optimized composition of 60% graphite, 14.2% paraffin, 10.8% MWCNT and 15% IL. The optimal modified CPE shows good electrochemical properties that are well matched with model prediction parameters. In the next step, the optimized CPE was modified with gold nanostructures by applying a double-pulse electrochemical technique. The resulting electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and electrochemical impedance spectroscopy. It gives three sharp and well-separated oxidation peaks for ascorbic acid (AA), dopamine (DA), and uric acid (UA). The sensor enables simultaneous determination of AA, DA and UA with linear responses from 0.3 to 285, 0.08 to 200, and 0.1 to 450 μM, respectively, and with 120, 30 and 30 nM detection limits (at an S/N of 3). The method was successfully applied to the determination of AA, DA, and UA in spiked samples of human serum and urine.