Determination of Salicylic Acid Using a Highly Sensitive and New Electroanalytical Sensor

Background:

A drug sensor (salicylic acid, in this case) was designed and made up of this research. The senor was made by modification of paste electrode (MPE) with CuO-SWCNTs and 1-hexyl-3-methylimidazolium chloride (HMICl). The MPE/CuO-SWCNTs/HMICl showed catalytic activity for the oxidation signal of salicylic acid in phosphate buffer solution.

Methods:

Electrochemical methods were used as a powerful strategy for the determination of salicylic acid in pharmaceutical samples. Aiming at this goal, carbon paste electrode was amplified with conductive materials and used as a working electrode.

Results:

The MPE/CuO-SWCNTs/HMICl was used for the determination of salicylic acid in the concentration range of 1.0 nM – 230 µM using differential pulse voltammetric (DPV) method. At pH=7.0, as optimum condition, the MPE/CuOSWCNTs/HMICl displayed a high-quality ability for the determination of salicylic acid in urine, pharmaceutical serum, and water samples.

Conclusion:

The MPE/CuO-SWCNTs/HMICl was successfully used as a new and high performance working electrode for the determination of salicylic acid at a nanomolar level and in real samples.

Recent Advantages of Mediator Based Chemically Modified Electrodes; Powerful Approach in Electroanalytical Chemistry

Background:

Modified electrodes have advanced from the initial studies aimed at understanding electron transfer in films to applications in areas such as energy production and analytical chemistry. This review emphasizes the major classes of modified electrodes with mediators that are being explored for improving analytical methodology. Chemically modified electrodes (CMEs) have been widely used to counter the problems of poor sensitivity and selectivity faced in bare electrodes. We have briefly reviewed the organometallic and organic mediators that have been extensively employed to engineer adapted electrode surfaces for the detection of different compounds. Also, the characteristics of the materials that improve the electrocatalytic activity of the modified surfaces are discussed.

Objective:

Improvement and promotion of pragmatic CMEs have generated a diversity of novel and probable strong detection prospects for electroanalysis. While the capability of handling the chemical nature of the electrode/solution interface accurately and creatively increases , it is predictable that different mediators-based CMEs could be developed with electrocatalytic activity and completely new applications be advanced.

Properties and Recent Advantages of N,N’-dialkylimidazolium-ion Liquids Application in Electrochemistry

:

N,Nʹ-dialkylimidazolium-ion liquids is one of the important ionic liquids with a wide range of application as conductive electrolyte and in electrochemistry. The modified electrodes create a new view in fabrication of electroanalytical sensors. Many modifiers have beeen suggested for modification of electroanalytical sensor since many years ago. Over these years, ionic liquids and especially room temperature ionic liquids have attracted more attention due to their wide range of electrochemical windows and high electrical conductivity. N,Nʹ-dialkylimidazolium-ion liquids are one of the main important ionic liquids suggested for modification of bare electrodes and especially carbon paste electrodes. Although many review articles have reported onthe use of ionic liquids in electrochemical sensors, no review article has been specifically introduced so far on the review of the advantages of N,Nʹ-dialkylimidazolium ionic liquid. Therefore, in this review paper we focused on the introduction of recent advantages of N,Nʹ-dialkyl imidazolium ionic liquid in electrochemistry.

Nano optical and electrochemical sensors and biosensors for detection of narrow therapeutic index drugs

For the first time, a comprehensive review is presented on the quantitative determination of narrow therapeutic index drugs (NTIDs) by nano optical and electrochemical sensors and biosensors. NTIDs have a narrow index between their effective doses and those at which they produce adverse toxic effects. Therefore, accurate determination of these drugs is very important for clinicians to provide a clear judgment about drug therapy for patients. Routine analytical techniques have limitations such as being expensive, laborious, and time-consuming, and need a skilled user and therefore  the nano/(bio)sensing technology leads to high interest.

Electrochemical sensors for β-adrenoceptor agonist isoprenaline analysis in human urine and serum samples using manganese cobalt oxide-modified glassy carbon electrode

Schematic illustration for the synthesis of the MCO nanosphere and modification with GCE towards the electrochemical determination of isoprenaline.

Voltammetric Determination of Glutathionein Pharmaceutical and Biological Samples Using Multiwall Carbon Nanotubes Paste Electrode in the Presence of Rutin as a Mediator

A new sensitive and selective electrochemical sensor was developed for electrocatalytic determination of glutathione (GSH) in pharmaceutical and biological samples. GSH is a tripeptidethiol present in all eukaryotic and probiotic cells. A voltammetric study of GSH has been carried out at the surface of carbon paste electrode modified with multiwall carbon nanotubes in the presence of rutin as a mediator. The electrochemical oxidation of GSH was investigated by cyclic voltammetry, chronoamperometry and square wave voltammetry (SWV) techniques. Under the optimized conditions, the peak current was linear to GSH concentration over the concentration range of 0.3 to 180μmol L⁻¹ using SWV. The detection limit was 0.09μmol L⁻¹. The proposed method was successfully applied to the determination of GSH in the urine, tablet and hemolysed erythrocyte samples.

Spectroelectrochemical Determination of Isoprenaline in a Pharmaceutical Sample

UV/Vis absorption spectroelectrochemistry (SEC) is a multi-response technique that has been commonly used for the characterization of materials and the study of reaction mechanisms. However, it has been scarcely used for quantitative purposes. SEC allows us to obtain two analytical signals simultaneously, yielding a dual sensor in just one experiment. In the last years, our group has developed new devices useful for analysis. In this work, a SEC device in parallel configuration, based on optical fibers fixed on screen-printed electrodes, was used to determine isoprenaline in a commercial drug, using both, the electrochemical and the spectroscopic signals. In this commercial drug, isoprenaline is accompanied in solution by other compounds. Among them is sodium metabisulfite, an antioxidant that strongly interferes in the isoprenaline determination. A simple pretreatment of the drug sample by bubbling wet-air allows us to avoid the interference of metabisulfite. Here, we demonstrate again the capabilities of UV/Vis absorption SEC as double sensor for analysis and we propose a simple pretreatment to remove interfering compounds.

Pt-Pd-doped NiO nanoparticle decorated at single-wall carbon nanotubes: An excellent, powerful electrocatalyst for the fabrication of An electrochemical sensor to determine nalbuphine in the presence of tramadol as two opioid analgesic drugs

In this study, a Pt-Pd-doped NiO nanoparticle decorated at the surface of single-wall carbon nanotubes (Pt-Pd/NiO-NPs/SWCNTs) was synthesized using a simple chemical precipitation method and characterized by XRD, TEM, and EDS methods. The results confirmed that Pt-Pd/NiO-NPs/SWCNTs were synthesized with good purity and at the nanoscale size. Moreover, a highly sensitive electroanalytical sensor was fabricated by incorporating synthesized Pt-Pd/NiO-NPs/SWCNT nanocomposites into a carbon paste electrode (CPE) in the presence of 1-ethyl-3-methylimidazolium methanesulfonate (EMICH₃SO₃^-) as binder. The Pt-Pd/NiO-NPs/SWCNTs/EMICH₃SO₃^-/CPE showed a powerful electro-catalytic activity for electro-oxidation of nalbuphine, and the results confirmed that the oxidation of nalbuphine was improved 6.34 times and relative oxidation potential was decreased about 110 mV compared to unmodified electrodes. The Pt-Pd/NiO-NPs/SWCNTs/EMICH₃SO₃^-/CPE also showed good catalytic activity for the determination of nalbuphine in the presence of tramadol and the oxidation potential of these opioid analgesic drugs separated with ΔE =460 mV. In the final step, the Pt-Pd/NiO-NPs/SWCNTs/EMICH₃SO₃^-/CPE was used to determine nalbuphine with a detection limit of 0.9 nM and tramadol with a detection limit of 50.0 nM in drug samples. The results confirmed the powerful and interesting ability of the sensor in the analysis of a real sample.

Developments and applications of nanomaterial-based carbon paste electrodes

This review summarizes the progress that has been made in the past ten years in the field of electrochemical sensing using nanomaterial-based carbon paste electrodes. Following an introduction into the field, a first large section covers sensors for biological species and pharmaceutical compounds (with subsections on sensors for antioxidants, catecholamines and amino acids). The next section covers sensors for environmental pollutants (with subsections on sensors for pesticides and heavy metal ions). Several tables are presented that give an overview on the wealth of methods (differential pulse voltammetry, square wave voltammetry, amperometry, etc.) and different nanomaterials available. A concluding section summarizes the status, addresses future challenges, and gives an outlook on potential trends.

This review summarizes the progress that has been made in the past ten years in the field of electrochemical sensing using nanomaterial-based carbon paste electrodes.

Simultaneous determination of isoproterenol, acetaminophen, folic acid, propranolol and caffeine using a sensor platform based on carbon black, graphene oxide, copper nanoparticles and PEDOT:PSS

We explored the use of carbon black (CB), graphene oxide (GO), copper nanoparticles (CuNPs) and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as electrode materials for the simultaneous determination of isoproterenol, acetaminophen, folic acid, propranolol and caffeine. The designed nanostructured surface was widely characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), contact angle measurements and electrochemistry. From electrochemical characterization assays carried out towards the potassium ferricyanide redox probe, fast electron transfer kinetics and a considerably higher electroactive surface area were observed for the modified electrodic surface based on CB, GO, CuNPs and PEDOT:PSS film. Using square-wave voltammetry (SWV), well defined and resolved anodic peaks were detected for isoproterenol, acetaminophen, folic acid, propranolol and caffeine, with peak-to-peak potential separation not less than 170 mV. Then, the SWV technique was explored for the simultaneous determination of quinary mixtures of these analytes, resulting in analytical curves with linear ranges and limits of detection at micromolar concentration levels. The practical viability of the proposed voltammetric sensor was illustrated in the analysis of human body fluid samples. The proposed sensor showed good repeatability and a successful application using urine and serum matrices, with recoveries close to 100%.

Preparation, characterization and analytical application of an electrochemical laccase biosensor towards low level determination of isoprenaline in human serum samples

A novel electrochemical biosensor has been developed based on the immobilization of multiwalled carbon nanotubes (MWCNT) followed by sol–gel entrapment of laccase (Lac) enzyme on to the GCE.

A new strategy for the selective determination of glutathione in the presence of nicotinamide adenine dinucleotide (NADH) using a novel modified carbon nanotube paste electrode

A novel electrochemical sensor for the simultaneous determination of glutathione (GSH) and nicotinamide adenine dinucleotide (NADH) is described. The sensor is based on a carbon paste electrode (CPE) modified with benzamide derivative and multiwall carbon nanotubes. This mixture makes a modified electrode that is sensitive for the electrochemical detection of these compounds. Under optimum conditions and at pH 7.0, oxidation of GSH occurs at a potential of about 330 mV less positive than that at an unmodified CPE. The voltammetric peak currents are linearly dependent on GSH and NADH concentrations in the ranges 0.09-300 μmol L(-1) GSH and 5.0-600 μmol L(-1) NADH. The detection limits found for GSH and NADH were 0.05 μmol L(-1) and 1.0 μmol L(-1), respectively. The electrochemical sensor was also used for the determination of GSH in urine, pharmaceutical and hemolysed erythrocyte samples.

Voltammetric determination of homocysteine using multiwall carbon nanotube paste electrode in the presence of chlorpromazine as a mediator

We propose chlorpromazine (CHP) as a new mediator for the rapid, sensitive, and highly selective voltammetric determination of homocysteine (Hcy) using multiwall carbon nanotube paste electrode (MWCNTPE). The experimental results showed that the carbon nanotube paste electrode has a highly electrocatalytic activity for the oxidation of Hcy in the presence of CHP as a mediator. Cyclic voltammetry, double potential step chronoamperometry, and square wave voltammetry (SWV) are used to investigate the suitability of CHP at the surface of MWCNTPE as a mediator for the electrocatalytic oxidation of Hcy in aqueous solutions. The kinetic parameters of the system, including electron transfer coefficient, and catalytic rate constant were also determined using the electrochemical approaches. In addition, SWV was used for quantitative analysis. SWV showed wide linear dynamic range (0.1-210.0 μM Hcy) with a detection limit of 0.08 μM Hcy. Finally, this method was also examined as a selective, simple, and precise electrochemical sensor for the determination of Hcy in real samples.