Electrochemical study of glimepiride and its complexation with β-cyclodextrin

2010 ◽  
Vol 76 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Abd-Elgawad M. Radi ◽  
Shimaa H. Eissa
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Glassy Carbon ◽  
Phosphate Buffer ◽  
Differential Pulse ◽  
Uv Spectrophotometry ◽  
Carbon Paste ◽  
Pulse Voltammetry ◽  
Ph Range ◽  
Tablet Dosage

The electrochemical behavior of a hypoglycemic drug, glimepiride (GM), was studied at glassy carbon (GCE) and carbon paste (CPE) electrodes in phosphate buffer over the pH range of 2.7–11.7 using cyclic and differential pulse voltammetry. Oxidation of the drug was shown to be an irreversible and diffusion-controlled process. Using differential pulse voltammetry (DPV), the drug yielded a well-defined voltammetric peak in phosphate buffer pH 6.4 at +1.16 V and pH 7.0 at +1.07 V (vs Ag|AgCl) on glassy carbon and carbon paste electrodes, respectively. This process could be used to determine glimepiride concentrations in the range from 1.0 × 10–5 to 3.2 × 10–5 mol l–1 with a detection limit of 2.0 × 10–6 mol l–1 in case of the glassy carbon electrode and in the range of 2.0 × 10–6 to 1.5 × 10–5 mol l–1 with a detection limit of 7.5 × 10–7 mol l–1 in case of the carbon paste electrode. The method was successfully applied to the determination of the drug in a tablet dosage form. Next, the formation of an inclusion complex of glimepiride with β-cyclodextrin (β-CD) in phosphate buffer (pH 7.0):methanol (90:10 (v/v)) has been investigated by differential pulse voltammetry as well as UV spectrophotometry and its stability constant was determined by both methods to be 202.0 and 197.9 l mol–1, respectively.

Determination of chloramphenicol by differential pulse voltammetry at carbon paste electrodes – The use of sodium sulfite for removal of oxygen from electrode surface

2011 ◽  
Vol 76 (5) ◽  
pp. 383-397 ◽  
Author(s):  
Ferenc T. Pastor ◽  
Hana Dejmková ◽  
Jiří Zima ◽  
Jiří Barek
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon ◽  
Sodium Sulfite ◽  
Differential Pulse ◽  
Optimal Conditions ◽  
Carbon Paste ◽  
Tricresyl Phosphate ◽  
Carbon Paste Electrodes ◽  
Pulse Voltammetry

The possibility of determination of chloramphenicol by differential pulse voltammetry at four different carbon paste electrodes, in the full pH range (2–12) of Britton–Robinson (BR) buffer was investigated. Electrodes were prepared by mixing spectroscopic graphite powder or glassy carbon microbeads with mineral oil (Nujol) or tricresyl phosphate. Under optimal conditions (BR buffer pH 12, the electrode prepared from glassy carbon microbeads and tricresyl phosphate), linear calibration graph was obtained only in 10–5 M chloramphenicol concentration range. Determination of lower concentrations of chloramphenicol was complicated by irreproducible peak of oxygen from the carbon paste which overlapped with peak of chloramphenicol. Addition of sodium sulfite removed the oxygen peak without influence on the peak of chloramphenicol. Under optimal conditions (electrode paste made from glassy carbon microbeads, BR buffer pH 10 and 0.5 M sodium sulfite), straight calibration line was obtained in the 10–6 and 10–5 M chloramphenicol concentration range. Limit of determination was 5 × 10–7 mol/l.

scholarly journals Development of a Carbon Paste Electrode Containing Benzo-15-Crown-5 for Trace Determination of the Uranyl Ion by Using a Voltammetric Technique

2009 ◽  
Vol 92 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Sunil K Agrahari ◽  
Sangita D Kumar ◽  
Ashwini K Srivastava
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Modified Electrode ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Differential Pulse ◽  
Carbon Paste ◽  
Pulse Voltammetry ◽  
Paste Electrode

Abstract The interaction of macrocyclic compounds like crown ethers and UO22+ has been studied by electrochemical methods. A modified carbon paste electrode incorporating benzo-15-crown-5 (B15C5) was used to evaluate the electron transfer reaction of UO22+ by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Electrochemical impedance studies showed that charge transfer resistance was less for the B15C5-modified electrode than for the plain carbon paste electrode (PCPE). On the basis of these observations, a UO22+-sensitive crown ether chemically modified electrode (CME) for trace analysis was fabricated and investigated in aqueous solutions. It was found that a 5 B15C5CME for UO22+ showed a better voltammetric response than did the PCPE. UO22+ could be quantified at sub-μg/mL levels by differential pulse voltammetry with a detection limit of 0.03 μg/mL. By differential pulse adsorptive stripping voltammetry, UO22+ could be quantified in the working range of 0.002-0.2 μg/mL, with a detection limit of 1.1 μg/L. Simultaneous determination of UO22+, Pb2+, and Cd2+ was possible. The method was successfully applied to the determination of UO22+ in synthetic, as well as real, samples; the results were found to be comparable to those obtained by inductively coupled plasma-atomic emission spectroscopy.

scholarly journals Teknik Differential Pulse Voltammetry Menggunakan Elektroda Pasta Karbon Termodifikasi Fe2O3 untuk Penentuan Kadar Fe(III) dalam Air Laut di Pelabuhan Benoa Bali

2021 ◽  
Vol 17 (1) ◽  
pp. 54
Author(s):  
Irdhawati Irdhawati ◽  
Ni Putu Antari Dewi ◽  
Ida Ayu Gede Widihati
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Carbon Paste ◽  
The West ◽  
Quantitation Limit ◽  
Passenger Ships ◽  
Scan Rate ◽  
Pulse Voltammetry ◽  
Linear Concentration

<p>Pelabuhan Benoa merupakan salah satu pelabuhan di Provinsi Bali tempat berlabuhnya kapal/perahu nelayan, kapal penumpang, dan kapal untuk pariwisata. Aktivitas masyarakat di sekitar pelabuhan dapat menjadi sumber pencemar logam berat. Penelitian ini bertujuan untuk mengetahui hasil optimasi dan validasi elektroda pasta karbon tanpa modifikasi (EPK) dan EPK termodifikasi Fe<sub>2</sub>O<sub>3</sub> (EPK Fe<sub>2</sub>O<sub>3</sub>) dengan teknik <em>differential pulse voltammetry</em> (DPV) untuk pengukuran Fe(III) dalam sampel air laut di Pelabuhan Benoa. Parameter yang dioptimasi yaitu laju pindai dan komposisi Fe<sub>2</sub>O<sub>3</sub> dalam pasta karbon. Selanjutnya dilakukan validasi pengukuran, meliputi rentang konsentrasi linier, limit deteksi, limit kuantisasi, keberulangan, dan persen perolehan kembali. Hasil yang diperoleh yaitu laju pindai optimum 15 mV/s menggunakan EPK, menjadi<ins cite="mailto:Microsoft%20Office%20User" datetime="2021-02-27T20:39"> </ins>lebih cepat yaitu 20 mV/s menggunakan EPK Fe<sub>2</sub>O<sub>3</sub>. Komposisi <em>modifier</em> terbaik dalam pasta karbon sebesar 0,5%. Rentang konsentrasi linier pengukuran menggunakan EPK yaitu 5 ~ 100 mg/L menjadi 5 ~ 2000 mg/L pada EPK Fe<sub>2</sub>O<sub>3. </sub>Limit deteksi dan limit kuantisasi menggunakan EPK Fe<sub>2</sub>O<sub>3 </sub>masing-masing 0,5490 mg/L dan 0,5497 mg/L, lebih rendah daripada menggunakan EPK yaitu 1,0667 mg/L dan 1,0688 mg/L. Keberulangan pengukuran menghasilkan rasio Horwitz yang lebih kecil dari dua. Nilai persen perolehan kembali pengukuran larutan standar dengan matriks larutan sampel yang diambil pada tiga lokasi yang berbeda, yaitu pada Dermaga Barat 97,51±9,92% ; Dermaga Selatan 101,18±10,60%; dan Dermaga Timur 95,50±1,23%. Hasil pengukuran Fe(III) dalam sampel diperoleh 129,98±13,65 mg/L; 114,85±13,75 mg/L; dan 127,77±4,01 mg/L, masing-masing pada Dermaga Barat, Selatan, dan Timur.</p><p><strong>Differential Pulse Voltammetry Technique Using Fe<sub>2</sub>O<sub>3</sub> Modified Carbon Paste Electrode for Determination of Fe(III) Levels in Seawater at Benoa Harbor Bali. </strong>Benoa Port is one of the ports in the Province of Bali where fishing boats, passenger ships, and ships for tourism are anchored. Activities around the port can be a source of heavy metal pollutants. This study aims to optimize and validates carbon paste electrodes without modification (EPK) and modified by Fe<sub>2</sub>O<sub>3</sub> (EPK Fe<sub>2</sub>O<sub>3</sub>) using differential pulse voltammetry (DPV) techniques for Fe (III) measurements in seawater at Benoa Harbor. The optimized parameters were scan rate and the Fe<sub>2</sub>O<sub>3</sub> composition in carbon paste. Meanwhile, the validation was performed, including the range of linear concentration, detection limit, quantitation limit, repeatability, and percent of the recovery. The research found that the optimum scan rate was 15 mV/s using EPK, become faster to 20 mV/s using EPK Fe<sub>2</sub>O<sub>3</sub>. The optimum <em>modifier</em> composition in carbon paste was 0.5%. The linear concentration range of measurement using EPK was 5 ~ 100 mg/L to 5 ~ 2000 mg/L at EPK Fe<sub>2</sub>O<sub>3</sub>. The detection limit and the quantitation limit using EPK Fe<sub>2</sub>O<sub>3</sub> were 0.5490 mg/L and 0.5497 mg/L, respectively. Those are lower than the detection limit quantitation by EPK i.e., 1.0667 mg/L and 1.0688 mg/L, respectively. Repeated measurements produce a Horwitz ratio which is less than two. The percent of recovery value of the measurement of the standard solution with the sample solution matrix taken from the three different locations are 97.51±9.92% for the West Pier region; 101.18±10.60% for the South Pier region; and 95.50±1.23% for the East Pier region. The Fe(III) measurements to the different samples from the West Pier, South Pier, and East Pier regions were 129.98±13.65 mg/L; 114.85±13.75 mg/L; and 127.77±4.01 mg/L, respectively.</p>

Polarographic and voltammetric determination of 6-mercaptopurine and 6-thioguanine

1986 ◽  
Vol 51 (11) ◽  
pp. 2466-2472 ◽  
Author(s):  
Jiří Barek ◽  
Antonín Berka ◽  
Ludmila Dempírová ◽  
Jiří Zima
Keyword(s):  
Detection Limit ◽  
Differential Pulse Voltammetry ◽  
Detection Limits ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Differential Pulse Polarography ◽  
Hanging Mercury Drop Electrode ◽  
Pulse Polarography ◽  
Pulse Voltammetry

Conditions were found for the determination of 6-mercaptopurine (I) and 6-thioguanine (II) by TAST polarography, differential pulse polarography and fast-scan differential pulse voltammetry at a hanging mercury drop electrode. The detection limits were 10-6, 8 . 10-8, and 6 . 10-8 mol l-1, respectively. A further lowering of the detection limit to 2 . 10-8 mol l-1 was attained by preliminary accumulation of the determined substances at the surface of a hanging mercury drop.

Ultrasensitive Electrochemical Determination of Phosphate in water by Hydrophilic TiO2 modified Glassy Carbon Electrodes

2021 ◽  
Author(s):  
Yan Jin ◽  
Tong QI ◽  
Yuqing Ge ◽  
Jin Chen ◽  
Li juan Liang ◽  
...  
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Carbon Electrodes ◽  
Glassy Carbon Electrodes ◽  
Time Differential ◽  
Pulse Voltammetry ◽  
First Time

In this paper, ultrasensitive electrochemical determination of phosphate in water is achieved by hydrophilic TiO2 modified glassy carbon electrodes for the first time. Differential pulse voltammetry (DPV) method is proposed...

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