Browsing by Author "Ali, Hoshyar Saadi"

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The Analytical Evolution of Glibenclamide (Glyburide) Antidiabetic Agents: Analytical Tools, Challenges, and Future Trends
(Taylor & Francis inc, 2025) Barzani, Hemn A. H.; Anwar Omer, Rebaz; Salih Barzani, Khalamala Ibrahim; Sulaiman, Seerwan Hamadameen; Ali, Hoshyar Saadi
Glyburide (glibenclamide), a second-generation sulfonylurea, remains a cornerstone in the management of type 2 diabetes mellitus. However, its narrow therapeutic index and typically low plasma concentrations demand highly sensitive and reliable quantification methods for applications spanning pharmacokinetics, therapeutic drug monitoring, clinical diagnostics, pharmaceutical quality control, and environmental surveillance. This review provides a critical overview of four decades of methodological progress in glyburide analysis, synthesizing evidence from major scientific databases, including Scopus, Web of Science, ScienceDirect, PubMed, and Google Scholar. High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) have emerged as the gold-standard approaches, offering exceptional sensitivity, specificity, and reproducibility across diverse matrices. In contrast, spectrophotometric methods provide cost-effective and straightforward options for routine analyses, while electrochemical techniques, particularly voltammetry with nanotextured electrodes, demonstrate remarkable sensitivity, sustainability, and applicability to trace detection. Capillary electrophoresis, though less commonly adopted, offers distinct benefits in resolution and solvent economy. Critical challenges are highlighted, including the quantification of glyburide at clinically relevant levels (2-400 ng/mL in plasma, with LOD as low as 0.038 ng/mL and LOQ 1.5 ng/mL), as well as overcoming matrix interferences and stability issues. Rigorous method validation remains essential to ensure accuracy and clinical utility. Finally, this review identifies key future directions, emphasizing the integration of green analytical chemistry principles, miniaturized platforms, and nanostructured sensing technologies to advance selective, sensitive, and environmentally sustainable glyburide analysis. These innovations hold the potential to transform glyburide monitoring from laboratory-based methods to real-world applications, including point-of-care testing and environmental health monitoring.
Analytical Techniques for Methyldopa and Metabolites: A Comprehensive Review
(Taylor & Francis Ltd, 2025) Barzani, Hemn A. H.; Sulaiman, Seerwan Hamadameen; Omer, Rebaz Anwar; Mer, Ali Hussein; Ali, Hoshyar Saadi
Methyldopa, a centrally acting alpha 2-adrenergic agonist, remains a key antihypertensive drug, particularly prescribed for pregnant and renal-impaired patients. Its clinical significance has led to extensive research aimed at developing reliable analytical methods for its accurate, sensitive, and selective determination in pharmaceutical formulations and biological matrices. Relevant literature was retrieved from Scopus, Web of Science, ScienceDirect, PubMed, and Google Scholar, restricted to English-language publications. This review critically examines the diverse analytical approaches used for Methyldopa quantification, outlining their principles, advantages, limitations, and applicability in both advanced and resource-limited settings. Chromatographic methods, especially high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS/MS), remain the most robust techniques, offering excellent sensitivity (LOD: 10-50 ng/mL for HPLC; as low as 0.7-15 ng/mL for LC-MS/MS) with rapid analysis times. While LC-MS/MS provides superior detection, it is limited by high costs and technical expertise requirements. Electrochemical methods, particularly voltammetry, stand out for their affordability, rapid analysis, and feasibility in decentralized laboratories, achieving LOD values as low as 0.01-0.05 mu M. Spectrophotometric approaches, primarily UV-Vis, remain the simplest and most cost-effective options, making them useful for routine quality control, though with reduced selectivity and higher detection limits. Key analytical challenges include Methyldopa's low concentration in biological fluids, chemical instability, and matrix interferences. This review provides a comparative evaluation of chromatographic, spectrophotometric, and electrochemical techniques, emphasizing the need for portable, low-cost platforms to expand accessibility in therapeutic monitoring. Overall, it offers critical insights for advancing Methyldopa analysis and improving clinical management in diverse healthcare settings.
An Anodically Pretreated Boron-Doped Diamond Electrode Surface for Square-Wave Adsorptive Stripping Voltammetric Quantification of the Non-Absorbable Antibiotic Rifaximin in the Pharmaceutical Formulation
(Elsevier Science Sa, 2023) Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Yardim, Yavuz
This study presents an electroanalytical examination with the voltammetric technique for quantitatively evaluating rifaximin (RFX) using the non-modified boron-doped diamond (BDD) electrode. By utilizing cyclic voltammetry (CV) method, RFX illustrated only one well-defined, irreversible, adsorption-controlled by oxidation and reduction peak at about +0.64 V and +0.21 V, respectively, (vs Ag/AgCl) in 0.1 M HNO3 solution. The square-wave (SW) voltammetric technique examined the dependence of potentials and current intensities on the BDD electrode pretreatment, the nature of a supporting electrolyte, pH, and another characteristic. When the SW mode was used, a satisfactory linear response was achieved in 0.1 M HNO3 solution at +0.56 V (vs Ag/AgCl). The dynamic range is observed from 0.5 to 20.0 mu g mL-1 (6.36 x 10-7-2.54 x 10- 5 M) via a low limit of detection of 0.14 mu g mL-1 (1.7810-7 M). The applicability of the developed method for detecting RFX was exhibited in pharmaceutical formulation samples.
Comprehensive Evaluation of Analytical Techniques for the Quantification of Etoposide in Various Matrices
(Taylor & Francis Inc, 2025) Barzani, Hemn A. H.; Sulaiman, Seerwan Hamadameen; Omer, Rebaz Anwar; Ahmad, Sarbast Naser; Ali, Hoshyar Saadi
Etoposide (ETO) is a semi-synthetic derivative of podophyllotoxin that is a common topoisomerase II inhibitor in the care of testicular cancer, small-cell lung cancer, leukemias, and lymphomas. Though the utility of ETO is extensive, it is constrained by variable bioavailability, a narrow therapeutic index, and potential for severe toxicities, which necessitate accurate quantification of ETO in pharmaceutical, clinical, and environmental applications. For more than four decades, measures of ETO have been described and developed. Spectrophotometric methods offer simplicity and low cost but lack specificity for complex matrices. High-performance liquid chromatography (HPLC) remains the reference standard, particularly when coupled with UV, fluorescence, or mass spectrometry (LC-MS or MS/MS), and also serves as the established method for pharmacokinetics and therapeutic drug monitoring. Other techniques, including capillary electrophoresis and emerging analytical methods, offer complementary advantages for resolution-challenged applications, thereby enhancing quality in ultra-trace and portable approaches. This review provides a narrative account of all aspects of these measures, specifically considering the basic operating principles, advantages, and disadvantages of each, the complexity of stability, matrix challenges, and ultra-trace measures. The future perspective is the need for greener, cost-effective, and clinically adapted clinical technologies, which will ultimately improve etoposide monitoring practices and patient outcomes.
Determination of Indacaterol From Inhaler Capsules by Square-Wave Voltammetry at the Surface of the Boron-Doped Diamond Electrode
(Serbian Chemical Soc, 2025) Barzani, Hemn Abdulazeez H.; Ali, Hoshyar Saadi; Yardim, Yavuz
This research paper presents an electroanalytical investigation using the voltammetric method to quantify indacaterol maleate (IND) employing an unmodified boron-doped diamond (BDD) electrode. IND exhibited a distinct, irreversible oxidation peak at approximately 1.06 V (vs. Ag/AgCl) in a 0.1 mol L-1 phosphate buffer solution (PBS) with a pH of 2.5, as demonstrated by cyclic voltammetry (CV). A hypothetical mechanism for the electro-oxidation of IND, based on data gathered from CV investigations, was suggested. The square wave-adsorptive stripping voltammetric technique achieved acceptable linearity in PBS (pH 2.5) at approximately 0.90 V. The methodology demonstrated linearity within the concentration range of 1.0 to 30.0 mu g mL-1 (equivalent to 1.97x10-6-5.89x10-5 mol L-1) and yielded a limit of detection (LOD) of 0.22 mu g mL-1 (equivalent to 4.33x10-7 mol L-1). The proposed method's applicability was assessed through the sensing of IND in drug formulations.
Developing an Electroanalytical Procedure for the Determination of Caffeic Acid Phenethyl Ester at a Boron-Doped Diamond Electrode by the Use of Cationic Surfactant Media
(Elsevier Science Sa, 2022) Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Ozok, Hande Izem; Yardim, Yavuz
The aim of the present work is to describe voltammetric analysis of caffeic acid phenethyl ester (CAPE) by using a boron-doped diamond (BDD) electrode in the presence of the cationic surfactant. Using cyclic voltammetry, CAPE demonstrated a single well-defined, quasi-reversible, adsorption-controlled by oxidation and reduction peak at approximately +0.44 V & +0.22 V respectively, (vs. Ag/AgCl) in the Britton-Robinson buffer (BR, 0.04 mol L-1, pH 5.0). The obtained results showed that the oxidation peaks of CAPE are pH dependent (ranging from 2.0 to 6.0). The oxidation peak currents of CAPE were significantly increased by using cetyltrimethylammonium bromide (CTAB, cationic surfactant) in the selected supporting electrolyte. Under the optimum parameters of experiment, the linear relationship was found for CAPE determination in 0.04 mol L-1 BR buffer solution (pH 5.0) including 1 x 10(-4) mol L-1 CTAB at +0.41 V (vs. Ag/AgCl) (after 30 s accumulation at the open-circuit condition). The linear range was found with 0.01 to 1.0 mu g mL(-1) (3.5 x 10(-8)-3.5 x 10(-6) mol L-1) via the detection limit 0.0028 mu g mL(-1) (9.8 x 10(-9) mol L-1). The developed approach was used successfully to detect CAPE concentration in the model urine samples. To our knowledge, this is the first approach for electrochemically analyzing of CAPE.
Electroanalytical Sensing of Antidiabetic Drug Linagliptin by Using Square-Wave Voltammetry on the Boron-Doped Diamond Electrode
(Springer Wien, 2024) Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Yardim, Yavuz
This research paper presents an electroanalytical investigation utilizing voltammetry to quantify the antidiabetic drug linagliptin with an unmodified boron-doped diamond electrode. Using cyclic voltammetry, linagliptin exhibited a single, distinct, irreversible oxidation peak at around + 1.03 V (vs. Ag/AgCl) in a 0.1 mol dm-3 phosphate buffer solution at pH 7.4. The square-wave voltammetry technique achieved acceptable linearity at approximately + 0.94 V in PBS (pH 7.4). The methodology demonstrated linearity within the concentration range of 1.0 and 50.0 mu g cm-3 (equivalent to 2.1 x 10-6-1.1 x 10-4 mol dm-3) and yielded a limit of detection of 0.28 mu g cm-3 (equivalent to 5.9 x 10-7 mol dm-3). The investigation of the proposed method's applicability was ultimately conducted through the sensing of linagliptin in drug formulations. The established methodologies can serve as viable alternatives to other analytical techniques due to their cost-effectiveness, user-friendliness, efficiency, and ability to yield reliable and repeatable results.
Fast and Simple Voltammetric Sensing of Avanafil in the Pharmaceutical Formulation by Using Unmodified Boron-Doped Diamond Electrode
(Iapc Publishing, 2024) Ali, Hoshyar Saadi; Barzani, Hemn A. H.; Yardim, Yavuz
Background and purpose: Erectile dysfunction is a common issue among adult males involving difficulty in maintaining an erection, and it is often treated with fast -acting, low -side -effect drugs like avanafil (AVN), among other phosphodiesterase-5 inhibitors. Hence, developing fast, simple, and sensitive methods to detect AVN is crucial. Experimental approach: This study conducts an electroanalytical inquiry and provides a new voltammetric method for accurately analyzing AVN utilizing a boron -doped diamond (BDD) electrode without any modifications. Key results: In the Britton -Robinson buffer (BR, 0.04 mol L-1, -1 , pH 4.0), cyclic voltammetry showed a clearly defined and irreversible anodic peak at around +1.44 V relative to Ag/AgCl. The pH of the solution was shown to have an impact on the voltammetric signals of the oxidation peaks. A good linear response for AVN quantification was achieved using square -wave voltammetry. This was done in a 0.04 mol L-1 BR (pH 4.0) solution at a potential of +1.33 V ( vs. Ag/AgCl). The method exhibited a wide dynamic range of 0.5 to 30.0 p.g mL-1 -1 (1.0 to 62 p.mol L-1) -1 ) and a low limit of detection of 0.14 p.g mL-1 -1 (0.29 p.mol L-1). -1 ). The method proposed demonstrated suitability for determining AVN content in pharmaceutical formulations. The accuracy of the approach was demonstrated by comparing the results obtained using the developed method with those achieved using the UV-Vis spectrometry method. Conclusion: Our method simplifies the analytical process by eliminating the need for electrode modification, reducing both time and resource requirements while enhancing overall feasibility. (c) 2024 by the authors. This article is an open -access article distributed under the terms and conditions of the Creative Commons Attribution license ( http://creativecommons.org/licenses/by/4.0/ ).
First Electrochemical Investigation of the Potent Antibiotic Rifapentine: Enhanced Voltammetric Detection Using a Boron-Doped Diamond Electrode in Tween-Mediated Measurements
(Elsevier Science Sa, 2025) Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Yardim, Yavuz
A non-modified boron-doped diamond electrode provided excellent electrochemical sensing capabilities for detecting rifapentine (RPT) using square-wave voltammetry. RPT was measured by cyclic voltammetry with phosphate buffer solutions (PBS, 0.1 M, pH 2.5), which exhibited irreversible behavior with distinct oxidation peaks at approximately +0.53 V (PA1) and + 1.08 V (PA2). The oxidation of RPT is strongly influenced by both pH and the choice of supporting electrolytes. The addition of the non-ionic surfactant Tween 20 to the supporting electrolyte notably enhanced the anodic peak currents of RPT. RPT was measured using two anodic peaks. Under optimal experimental conditions and instrumental factors, the current response for RPT exhibited a linear relationship within the range of 1 to 25.0 mu g mL-1 (1.1 x 10-6-2.9 x 10-5 M), with detection limits of 0.29 mu g mL-1 (3.3 x 10- 7 M) for PA1 (+0.48 V) as well as 0.19 mu g mL-1 (2.2 x 10- 7 M) for PA2 (+1.04 V) in PBS (pH 2.5). Finally, RPT in a pharmaceutical formulation was accurately quantified using the proposed methodology. This represents, to the best of our knowledge, the first electroanalytical method for determining RPT.
First Electrochemical Study of a Potent Antifungal Drug Caspofungin: Application To Its Enhanced Voltammetric Sensing Based on the Performance of Boron-Doped Diamond Electrode in Ctab-Mediated Measurements
(Elsevier Science Sa, 2022) Ali, Hoshyar Saadi; Barzani, Hemn A. H.; Yardim, Yavuz; Senturk, Zuhre
This present study describes the first electrochemical investigation of caspofungin, which is a semisynthetic echinocandin class of antifungal drug. For this purpose, an electrochemically pretreated (anodically and subsequently cathodically) boron-doped diamond (BDD) electrode was used. The cyclic voltammetric scans showed a single oxidation step that is irreversible and controlled by a dual mechanism of adsorption and diffusion. For the optimization of experimental conditions, the influence of the electrode pretreatment, pH of the supporting electrolyte, concentration of cationic surfactant cetyltrimethylammonium bromide (CTAB), accumulation variables, and instrumental parameters was examined on the current response of caspofungin. The improved sensitivity of the voltammetric measurements was observed due to the synergistic effect of CTAB on the adsorption capacity of BDD electrode in alkaline pH conditions. Employing square-wave adsorptive stripping voltammetry (using open-circuit accumulation for 60 s), the oxidation signal at around +0.45 V allowed to the determination of caspofungin in Britton-Robinson buffer at pH 11.0 containing 1 x 10-4 M CTAB. The process could be used in the concentration range from 2.06 x 10-7 to 1.03 x 10-5 M (from 0.25 to 12.5 mu g mL-1 as acetate salt) with a detection limit of 5.27 x 10-8 M (0.064 mu g mL-1 as acetate salt). A technique developed here was used successfully to determine caspofungin concentration in commercial parenteral dosage formulations.
A New Approach for the Voltammetric Sensing of the Phytoestrogen Genistein at a Non-Modified Boron-Doped Diamond Electrode
(Wiley-v C H verlag Gmbh, 2022) Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Sahin, Cihat; Kiran, Musa; Yardim, Yavuz
An effective electrochemical sensor was constructed using an unmodified boron-doped diamond electrode for determination of genistein by square-wave voltammetry. Cyclic voltammetric investigations of genistein with HClO4 solution indicated that irreversible behavior, adsorption-controlled and well-defined two oxidation peaks at about +0.92 (P-A1) & +1.27 V (P-A2). pH, as well as supporting electrolytes, are important in genistein oxidations. Quantification analyses of genistein were conducted using its two oxidation peaks. Using optimized experiments as well as instrumental conditions, the current response with genistein was proportionately linear in the concentrations range of 0.1 to 50.0 mu g mL(-1) (3.7x10(-7)-1.9x10(-4) mol L-1), by the detection limit of 0.023 mu g mL(-1) (8.5x10(-8) mol L-1) for P-A1 and 0.028 mu g mL(-1) (1.1x10(-7) mol L-1) for P-A2 in 0.1 mol L-1 HClO4 solution (in the open circuit condition at 30 s accumulation time). Ultimately, the developed method was effectively applied to detect genistein in model human urine samples by using its second oxidation peak (P-A2).
Quantification of Ferulic Acid Using Square-Wave Voltammetric Method at an Unmodified Boron-Doped Diamond Electrode
(Springer Wien, 2023) Pinar, Pinar Talay; Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Yardim, Yavuz
For the first time, a boron-doped diamond electrode was employed in square-wave voltammetry for the sensitive and selective measurement of ferulic acid (FA). The impact of the electrode's pretreatment procedure on the current response was investigated, leading to the discovery that the consecutive pretreatment approach yielded the most optimal signal results. This determination was made upon observing that the highest quality signal could be obtained through this method. The electrochemical oxidation of FA was studied in aqueous media on a cathodically pretreated boron-doped diamond electrode. FA was shown to have two sets of oxidation/reduction peaks when tested in aqueous solutions using cyclic voltammetry. Diffusion governs the electrode process, which is pH-dependent. In 0.1 mol dm-3 H2SO4, the calibration curves were linear for FA peak over dynamic ranges of 5.1 x 10-7-4.1 x 10-5 mol dm-3, via a detection limit of 1.5 x 10-7 mol dm-3. The practical applicability of the developed methodology was tested in the commercial ampoule formulation of FA. The method can be used instead of other analytical methods because it is fast, easy to use, and cheap, has a wide calibration range, and gives consistent results.
Sensing Ivacaftor Accomplished Using the Square-Wave Voltammetric Technique With the Assistance of a Cationic Surfactant on a Boron-Doped Diamond Electrode
(Elsevier Science Sa, 2024) Barzani, Hemn A. H.; Ali, Hoshyar Saadi; Yunusoglu, Oruc; Yardim, Yavuz
This investigation aims to describe the voltammetric analysis of ivacaftor (IVA) by utilizing the boron -doped diamond (BDD) electrode to add a cationic surfactant. Cyclic voltammetry via Britton-Robinson (BR, 0.04 mol L-1, pH 2.0) buffer was used to perform determinations of the IVA demonstrating irreversible behaviors, adsorption-controlled and well-defined (+1.04 V, PA1) and an ill-defined (+1.42 V, PA2) oxidation peaks (vs. Ag/ AgCl). The findings revealed that the oxidation peaks of IVA are pH-dependent (ranging from 2.0 to 5.0). The use of cetyltrimethylammonium bromide (CTAB, cationic surfactant) in the chosen supporting electrolyte enormously raised the oxidation peak currents of IVA. For the measurement of IVA in a 0.04 mol L-1 BR buffer solution with a pH of 2.0, the linear relationship was discovered to exist under the conditions of the experimental optimal parameters involving 2 x 10-4 mol L-1 CTAB at +1.11 V (vs. Ag/AgCl) (after an accumulation of 60 s at the open-circuit condition). The linear concentration was discovered using 0.25 to 10.0 mu g mL-1 (6.4 x 10-7-2.5 x 10-5 mol L-1) and the limit of detection 0.073 mu g mL-1 (1.9 x 10-7 mol L-1). The devised methodology was effectively employed to determine IVA in pharmaceutical formulation. To the best of our understanding, it represents the first electroanalytical method for detecting IVA by voltammetry.
Simultaneous Estimation of Total Phenolic and Alkaloid Contents in the Tea Samples by Utilizing the Catechin and Caffeine Oxidation Signals Through the Square-Wave Voltammetry Technique
(Elsevier Sci Ltd, 2024) Ali, Hoshyar Saadi; Yardim, Yavuz
This work outlines the simultaneous estimation of the total phenolic and alkaloid contents in the tea samples by using catechin (C) and caffeine (CAF) oxidation signals at a non-modified boron-doped diamond (BDD) electrode. Two irreversible oxidation peaks, about + 1.03 (for C) and + 1.45 V (for CAF) vs Ag/AgCl in acetate buffer solution at pH 4.7, were seen in the cyclic voltammetric profile of the binary mixtures of C and CAF. In optimal conditions and utilizing the square-wave mode, the BDD electrode allows for simultaneous quantification of C and CAF within the concentration ranges of 5.0-100.0 mu g mL-1 (1.72 x 10-5 -3.45 x 10-3 mol/L) and 1.0-50.0 mu g mL-1 (5.15 x 10-6 -2.57 x 10-4 mol/L) respectively. The corresponding detection limits are 1.22 mu g mL-1 (4.21 x 10-6 mol/L) for C and 0.11 mu g mL-1 (5.66 x 10-7 mol/L) for CAF. Other phenolic compounds (like tannic acid, gallic acid, epicatechin, and epigallocatechin gallate) and other alkaloids (theophylline and theobromine) present in tea samples were examined for selectivity assessment. Ultimately, the applicability of the proposed approach was demonstrated by estimating the total phenolic and alkaloid contents in the black and green tea samples, expressed as C and CAF equivalents. The results obtained were contrasted against those acquired using UV-Vis spectrometry.
Simultaneous Voltammetric Determination of Vanillin and Caffeine in Food Products Using an Anodically Pretreated Boron-Doped Diamond Electrode: Its Comparison With Hplc-Dad
(Elsevier Science Bv, 2017) Ali, Hoshyar Saadi; Abdullah, Abdullah A.; Pinar, Pinar Talay; Yardim, Yavuz; Senturk, Zuhre
This paper describes an electroanalytical method for the simultaneous determination of vanillin (VAN) and caffeine (CAF) using an anodically pretreated boron-doped diamond electrode. Selective determination of one compound in the presence of other one was also realized. Both compounds yielded a single irreversible oxidation peak using cyclic voltammetry. The nature of the electrode reaction was found to be diffusion controlled with contribution of adsorption. By using square-wave adsorptive stripping voltammetry after 60 s accumulation under open-circuit voltage, method allowed simultaneous determination of VAN and CAF in phosphate buffer, pH 2.5, with detection limits of 0.234 g (1.54x10(-6) M) and 0.071 mu g mL(-1) (3.66x10(-7)M), respectively. The proposed method was successfully applied in the selective and simultaneous determination of VAN and CAF in commercial food and beverage samples. In addition, for the comparison, high-performance liquid chromatographic method with diode-array detection was developed for the first time for their simultaneous determination.
An Unmodified Boron-Doped Diamond Electrode for Electroanalytical Investigation and Sensitive Voltammetric Quantification of Antiviral Drug Famciclovir in the Pharmaceutical Formulation and Serum Samples
(Elsevier Science Sa, 2022) Yardim, Yavuz; Ali, Hoshyar Saadi; Barzani, Hemn A. H.
The current study offers an electroanalytical investigation and a novel voltammetric approach for the quanti-tative analysis of famciclovir (FCV) utilizing an unmodified boron-doped diamond (BDD) electrode. An irre-versible, well-defined, diffusion-controlled anodic peak was observed at approximately +1.27 V (vs. Ag/AgCl) in acetate buffer solution (ABS, 0.1 mol L-1, pH 4.7) when the agent was tested using cyclic voltammetry. The voltammetric signals of the oxidation peaks are pH dependent (ranging from 2.0 to 7.0). Using square-wave mode, a good linear response was obtained for FCV quantification in 0.1 mol L-1 ABS (pH 4.7) solution at +1.26 V (vs. Ag/AgCl). Wide dynamic range was found for 0.1 to 50.0 mu g mL-1 (3.11 x 10-( 7)-1.56 x 10(-4) mol L-1), with a low detection limit of 0.029 mu g mL-1 (9.02 x 10(-8) mol L-1). Applicability of the proposed method for the determination of FCV was demonstrated in the pharmaceutical formulation and model serum samples.
Utilization of a Simple and Fast Electroanalytical Method with an Unmodified Boron-Doped Diamond Electrode for Taxifolin Sensing in Food Supplement Samples
(Springer India, 2025) Ali, Hoshyar Saadi; Barzani, Hemn A. H.; Yardim, Yavuz
Using an unmodified boron-doped diamond electrode, an electrochemical sensor was established for the determination of taxifolin through square-wave voltammetry. Cyclic voltammetry measurements conducted in a 0.1 M HClO4 solution showed that taxifolin exhibits irreversible behavior with diffusion control, marked by distinct oxidation peaks at approximately + 1.04 V (PA1) and + 1.44 V (PA2) versus Ag/AgCl. Furthermore, the pH as well as the supporting electrolyte had an effect on the oxidation process. The quantification of taxifolin was based on its two anodic peaks. The optimized method yielded a current response that was linearly proportional to taxifolin concentration, ranging from 2.5 to 50.0 mu g mL-1 (8.2 x 10-6 to 1.6 x 10-4 M), with detection limits of 0.72 mu g mL-1 (2.4 x 10-6 M) for PA1 and 0.63 mu g mL-1 (2.1 x 10-6 M) for PA2 in HClO4. The method was successfully applied for the evaluation of taxifolin in a food supplement, thereby demonstrating its practical applicability. This study is among the first to utilize both oxidation peaks of taxifolin in electroanalytical measurements. Comparisons between the results obtained using this technique and those from the UV-Vis spectrometry method confirmed the accuracy of the approach.
Utilizing Epicatechin Voltammetric Oxidation Signal for the Estimation of Total Phenolic Content in the Tea Samples Via the Unmodified Boron-Doped Diamond Electrode Surface
(Elsevier, 2023) Ali, Hoshyar Saadi; Barzani, Hemn A. H.; Yardim, Yavuz
In this work, the boron-doped diamond (BDD) electrode surface was employed for the first time in conjunction with the epicatechin (EC) oxidation signal to estimate the total phenolic content of tea samples by voltammetry. During cyclic voltammetry analysis of the EC, an easily identifiable, irreversible, and adsorption-controlled oxidation peak was observed at around +1.05 V (vs. Ag/AgCl) in HNO3 solution. Our experimental setup was fine-tuned by investigating the effect of electrode pretreatment, pH of the supporting electrolyte, accumulation factors, and instrumental parameters on the oxidation peak response of EC. When measuring EC in a 0.1 mol L-1 HNO3 solution at +1.0 V, square-wave adsorptive stripping voltammetry provided a highly linear response (at open-circuit accumulation for 30 s). The dynamic range was determined to be between 1.0 and 50.0 mu g mL-1 (3.4510-6-1.7210-4 mol L-1), while the detection limit was found to be 0.28 mu g mL-1 (9.6510-7 mol L-1). Selectivity studies were performed with other phenolic compounds found in tea such as epigallocatechin gallate, catechin, tannic acid, and gallic acid. Finally, by assessing the total phenolic content in the black and green tea samples, the suggested approach's applicability was shown by providing an estimate of the EC equivalents present in the samples.