CTAB immobilized carbon paste electrode for the determination of mesalazine: A cyclic voltammetric method

Development of a Diethylcarbamazine Citrate‐Based Electrochemical Sensor for Quick and Affordable Detection of Sulfadiazine and Uric Acid in Environmental Monitoring

The widespread use of antibiotics like sulfadiazine (SDZ) in various industries has raised environmental and health concerns due to their potential for bioaccumulation and the subsequent effects on human health and the environment. Diethylcarbamazine citrate (DCZ), a well‐established antifilarial drug, has yet to be explored as a sensing agent despite its extensive use. This study proposes a cost‐effective and efficient method for detecting SDZ and Uric acid (UA) using a DCZ‐modified carbon paste electrode (poly‐DCZ/MCPE). The poly‐DCZ film is synthesized via cyclic voltammetry (CV) on the carbon paste electrode surface, demonstrating excellent electrocatalytic activity for SDZ and UA detection at pH 7.4. The diffusion‐controlled electrode process is observed with a lower limit of detection (LOD) and limit of quantification (LOQ) for SDZ as 3.8×10−9 M and 12.94×10−9 M respectively. For UA, LOD and LOQ were found to be 6.291×10−9 M and 20.97×10−9 M respectively at the poly‐DCZ/MCPE. Notably, the sensor exhibits simultaneous detection capabilities for SDZ and UA by CV and differential pulse voltammetry (DPV) methods, addressing the need to monitor antibiotic residues in aquatic ecosystems and animal‐derived products.

Electroanalytical Overview: The Sensing of Mesalamine (5-Aminosalicylic Acid)

Mesalamine, known as 5-aminosalicylic acid, is a medication used primarily in the treatment of inflammatory bowel disease, including ulcerative colitis and Crohn's disease. 5-Aminosalicylic acid can be measured using various benchtop laboratory techniques which involve liquid chromatography-mass spectroscopy, but these are sophisticated and large, meaning that they cannot be used on-site because transportation of the samples, chemicals, and physical and biological reactions can potentially occur, which can affect the sample's composition and potentially result in inaccurate results. An alternative approach is the use of electrochemical based sensing platforms which has the advantages of portability, cost-efficiency, facile miniaturization, and rapid analysis while nonetheless providing sensitivity and selectivity. We provide an overview of the use of the electroanalytical techniques for the sensing of 5-aminosalicylic acid and compare them to other laboratory-based measurements. The applications, challenges faced, and future opportunities for electroanalytical based sensing platforms are presented in this review.

Determination of Exogenous Adrenaline Levels in Patients Undergoing Cardiopulmonary Resuscitation

Core-shell quantum dot ZnS/CdSe screen-printed electrodes were used to electrochemically measure human blood plasma levels of exogenous adrenaline administered to cardiac arrest patients. The electrochemical behavior of adrenaline on the modified electrode surface was investigated using differential pulse voltammetry (DPV), cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). Under optimal conditions, the linear working ranges of the modified electrode were 0.001-3 μM (DPV) and 0.001-300 μM (EIS). The best limit of detection for this concentration range was 2.79 × 10^-8 μM (DPV). The modified electrodes showed good reproducibility, stability, and sensitivity and successfully detected adrenaline levels.

Synergetic effects of a poly-tartrazine/CTAB modified carbon paste electrode sensor towards simultaneous and interference-free determination of benzenediol isomers

Simultaneous and selective detection of dihydroxy benzene isomers by the synergistic effect of CTAB and tartrazine on a carbon paste electrode (poly-TZ/CTAB/MCPE) sensor by CV and DPV techniques.

Properties of a furan ring-opening reaction in aqueous micellar solutions for selective sensing of mesalazine

A novel and efficient non-azo formation based method was developed for trace sensing of mesalazine (MES), a pharmaceutical aromatic amine. MES was simply coupled with a Meldrum's activated furan (MAF) reagent via a furan ring opening reaction to form a colored product. The intense purple colored solution was detected at 575 nm. The reaction of MES with MAF was monitored by employing ¹H NMR spectroscopy and mass spectrometry. In addition, density functional theory (DFT) was applied to optimize the structure of the colored product and its λ_max (the wavelength of maximum absorbance) in dimethyl sulfoxide and water. The colored product was considered in three possible structures, and the most possible structures in dimethyl sulfoxide and in water were identified by employing the DFT calculations. Both of the most possible structures indicated only a local excitation in their λ_max and no charge transfer was observed. However, one of the structures in dimethyl sulfoxide presented charge transfer properties occurring through NCCC moiety. A univariate optimization method was also used to attain the optimum condition for analysis. In addition, the dependence of the analytical response on the three main affecting parameters (reaction time (X₁), Triton X-100 concentration (X₂) and MAF concentration (X₃)) was identified by employing a central composite design (CCD) approach. The CCD study showed that the analytical response depends complexly on the parameters. Beer's law was obeyed within the range of 0.06-9.30 μg mL^-1 of MES (155 fold linearity) at 575 nm, under the optimum condition introduced by the CCD approach. Also, the limit of detection was obtained 0.04 μg mL^-1 of MES. The method showed precision (as relative standard deviation) and accuracy (as recovery) within the ranges of 0.6-3.2 % and 96.3-100.8%, respectively. Various organic and inorganic species, amino-pharmaceuticals, and amino acids were tested to evaluate the selectivity of the method. The selectivity of the analytical method was satisfactory. The method was successfully applied for detection of MES in various water matrices and pharmaceutical tablets.

Mixture of carbon aerogel with Pd-WO3 nanorods for amperometric determination of mesalazine

We prepared, for the first time, carbon aerogels support on Pd-WO₃ nanorods (CAs/Pd-WO₃) hybrid nanocomposite via sol-gel and microwave-assisted methods. The as-prepared CAs/Pd-WO₃-modified electrode was used as effective electrocatalyst for nanomolar level detection of mesalazine (MSA). The typical porous nature of carbon aerogels effectively prevented the aggregation of Pd-doped WO₃ nanorods and increased the electrochemically active surface area. In addition, the Pd-WO₃ nanointerface provides intrinsic improvement of the electrocatalytic activity and stability for the electrochemical oxidation process, and the interconnected conducting network of the porous surfaces of CAs accelerated rapid electron transport at the working electrode. The synergistic effect of the CAs/Pd-WO₃ architecture has excellent electrocatalytic activity for the detection of MSA with high sensitivity of 2.403 ± 0.004 μA μM^-1 cm^-2, low detection limit of 0.8 ± 0.3 nM and wide linear response from 0.003-350 μM at a low applied potential of 0.30 V vs. Ag|AgCl. Satisfactory results were observed for its analytical performance in detecting MSA in human blood serum and urine samples, and recoveries ranged from 98.8 to 100.4%. We believe that the architecture of the modified CAs/Pd-WO₃ electrocatalysts can be effectively used in clinical applications for the detection of MSA.

Ni-Doped ZrO2 nanoparticles decorated MW-CNT nanocomposite for the highly sensitive electrochemical detection of 5-amino salicylic acid

Ni-ZrO₂/MWCNT/GCE for highly sensitive electrochemical detection of 5-ASA in biofluids.

A Novel Approach for Effective Alteration of Morphological Features of Polyaniline through Interfacial Polymerization for Versatile Applications

Morphological characteristics of any nanomaterial are critical in defining its properties. In this context, a method to control morphological parameters of polyaniline (PANI) has been investigated by producing its composite with gold nanoparticles (AuNPs). Herein, we report for the first time the successful control on the physical/chemical properties of PANI composites synthesized via interfacial polymerization through functionalization of its AuNP composite component with citrate, ascorbate, glutathione (GSH), and cetyl trimethyl ammonium bromide (CTAB). A significant difference in the polymerization pattern, morphologies, and electrical properties was recognized in these composites according to the functionality of the modified AuNPs. The obtained composites of AuNPs/PANI exhibited highly diverse morphologies (e.g., nodule, hollow hemisphere, flake, and spider-web galaxy type) and electrical characteristics according to functionalization. Hence, this study is expected to offer better insight into control of the polymerization pattern of AuNP/PANI composites and their associated properties.

Design of a Sensitive and Selective Voltammetric Sensor Based on a Cationic Surfactant-Modified Carbon Paste Electrode for the Determination of Alloxan

Alloxan (AL) is a toxic glucose analogue that acts as a potent diabetogenic inducer by selectively destroying the insulin-producing β-cells of the pancreas. Hence, a sensitive and selective cetyl trimethylammonium bromide (CTAB)-immobilized carbon paste electrode was utilized for the analysis of AL in the existence of anthrone. The CTAB-modified carbon paste electrode in contrast with the bare carbon paste electrode showed a magnificent behavior for the electrocatalytic oxidation of AL by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. CV studies reveal a quasi-reversible diffusion-controlled process in the potential window of -0.5 to 0.4 V at an optimum pH of 6.5 in 0.2 M phosphate buffer solution. The electrode materials were characterized by CV, field emission-scanning electron microscopy, and electrochemical impedance spectroscopy. Under optimized experimental conditions, low detection limits of 1.09 and 3.64 μM were obtained in a linear dynamic range of 5-80 μM and from 8 to 90 μM by DPV and CV methods, respectively. The performance of the modified electrode is impressive in terms of least charge transfer resistance (R ct), surface concentration (Γ), and heterogeneous electron transfer rate constant (k 0). A 50-fold excess concentration of other potential interferants such as food additives and other organic species present in the human body does not significantly alter the peak potential and peak current of AL. The analytical application of the modified sensor was appraised by determining AL in the spiked refined flour sample. The modified sensor with a swift fabrication procedure exhibited enduring stability, adequate reproducibility, and acceptable repeatability.

Surfactant Modified Graphite Paste Electrode as an Electrochemical Sensor for the Enhanced Voltammetric Detection of Estriol with Dopamine and Uric acid

Purpose: Estriol (ERL) is a type of hormone among the groups of estrogen hormone that was detected through the voltammetric technique by constructing an electrochemical sensor based on the octoxynol-9 modified graphite paste electrode (OXL-9MGPE). Methods: Using the strategy of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with a bare graphite paste electrode (BGPE) immobilized with OXL-9, ERL electro-oxidation has been assessed in 0.2 M phosphate buffer solution (PBS) of pH 6.0. The fabricated electrode has substantial electrochemical sensing efficiency, and the ERL oxidation at the OXL-9MGPE was the irreversible process. The surface morphological characteristics of BGPE and OXL-9MGPE were differentiated with the help of field emission scanning electron microscopy (FE-SEM). Results: The impact of various factors such as scan rate, pH, reproducibility, repeatability, and stability on the electro-oxidation of ERL was evaluated. Techniques of CV and DPV were utilized to determine ERL, dopamine (DAN), and uric acid (URA) simultaneously with the projected sensor. The peak current was varied with ERL concentration in the range from 4×10-5 to 1.2×10-4 M at OXL-9MGPE. From this, the detection limit 1.4×10 -6 M and limit of quantification (LOQ) 4.7×10-6 M have been attained. Conclusion: As a result, OXL-9MGPE was successfully achieved as an electrochemical detector for the electro analysis of ERL via the CV technique.

Voltammetric determination of iodide in iodized table salt using cetyltrimethylammonium bromide as ion-pairing

In this work, voltammetric study based on cetyltrimethylammonium bromide (CTAB) as an ion-pairing agent for the determination of iodine level in iodized table salt has been explored. CTAB was used as an intermediate compound between iodide (I^-) and the electrode due to its ability to dissociate to produce cetyltrimethylammonium ions ([CTA]⁺). The [CTA]⁺ with a long hydrophobic alkyl chain can be directly adsorbed onto the surface of the working electrode, and this in turns coated the electrode with cationic charge and enhance the electrode ability to bind to iodide (I^-) and other molecular iodine ions. A mixture of iodide and CTAB ([CTA]⁺I^-) was prepared and potential of 1.0 V for 60.0 s was applied to pre-concentrate the solution on the working electrode causing the [CTA]⁺I^- to oxidize to iodine (I₂). The produced I₂ immediately react with chloride ion (Cl^-) from the electrolyte of hydrochloric acid (HCl) to produce I₂Cl^- and form ion-pair with CTA⁺ as [CTA]⁺I₂Cl^-. The linear calibration curve of the developed method towards iodide was in the concentration range of 0.5-4.0 mg/L with sensitivity of - 1.383 µA mg/L^-1 cm^-2 (R² = 0.9950), limit of detection (LOD) of 0.3 mg/L and limit of quantification (LOQ) of 1.0 mg/L, respectively. The proposed method indicates good agreement with the standard method for iodine determination with recovery range from 95.0 to 104.3%. The developed method provided potential application as a portable on-site iodine detector.