scholarly journals Improved Voltammetric Determination of Kynurenine at the Nafion Covered Glassy Carbon Electrode – Application in Samples Delivered from Human Cancer Cells

2021 ◽  
Vol 14 ◽  
pp. 117864692110234
Author(s):  
Ilona Sadok ◽  
Katarzyna Tyszczuk-Rotko ◽  
Robert Mroczka ◽  
Jędrzej Kozak ◽  
Magdalena Staniszewska
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Accurate Determination ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Reliable Determination ◽  
Accumulation Time ◽  
Cell Extracts

Nowadays, development of analytical methods responding to a need for rapid and accurate determination of human metabolites is highly desirable. Herein, an electrochemical method employing a Nafion-coated glassy carbon electrode (Nafion/GCE) has been developed for reliable determination of kynurenine (a key tryptophan metabolite) using a differential pulse adsorptive stripping voltammetry. To our knowledge, this is the first analytical method to allow for kynurenine determination at the Nafion-coated electrode. The methodology involves kynurenine pre-concentration in 0.1 M H2SO4 in the Nafion film at the potential of +0.5 V and subsequent stripping from the electrode by differential pulse voltammetry. Under optimal conditions, the sensor can detect 5 nM kynurenine (for the accumulation time of 60 seconds), but the limit of detection can be easily lowered to 0.6 nM by prolonging the accumulation time to 600 seconds. The sensor shows sensitivity of 36.25 μAμM−1cm−2 and 185.50 μAμM−1cm−2 for the accumulation time of 60 and 600 seconds, respectively. The great advantage of the proposed method is easy sensor preparation, employing drop coating method, high sensitivity, short total analysis time, and no need for sample preparation. The method was validated for linearity, precision, accuracy (using a high-performance liquid chromatography), selectivity (towards tryptophan metabolites and different amino acids), and recovery. The comprehensive microscopic and electrochemical characterization of the Nafion/GCE was also conducted with different methods including atomic force microscopy (AFM), optical profilometry, time-of-flight secondary ion mass spectrometry (TOF-SIMS), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The method has been applied with satisfactory results for determination of kynurenine concentration in a culture medium collected from the human ovarian carcinoma cells SK-OV-3 and to measure IDO enzyme activity in the cancer cell extracts.

scholarly journals Preparation and Application of Keggin Silicomolybdic acid Modified Electrode

2020 ◽  
Author(s):  
Miao Liu ◽  
Mingxuan Jia ◽  
Dong Hui Li
Keyword(s):  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Photoelectron Spectroscopy ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
X Ray ◽  
Linear Relationships

Abstract An innovative method for the determination of isoniazid tablets is studied through electrochemical method for the modification of glassy carbon electrode (GCE). Polyoxomolybdate, with stable structures, has not been widely used for the determination of substance. In this study, the mentioned polyoxomolybdate was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, X-ray diffraction (XRD), Atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), and used to modify the glassy carbon electrode. The electrochemical performance of the polyoxomolybdate@GCE was investigated with cyclic voltammetry (CV) and differential pulse voltammetry (DPV), compared with the unmodified electrode, the proposed polyoxomolybdate modified electrode exhibited strong electro-catalytic activities towards isoniazid (INH). Under the optimized conditions, there was linear relationships between the DPV peak currents and the concentrations in the range of 1 × 10 -7 g/L to 3 × 10 -7 g/L for INH (R 2 = 0.9979), with the limit of detection (LOD) of 0.024 μg/L (based on S/N = 3). The modified electrode has proper reproducibility (RSD < 5%), stability, response time (< 3 min) and lifetime (up to 6 days).

Voltammetry Determination of Cefotaxime on Zinc Oxide Nanorod Modified Electrode

2020 ◽  
Vol 17 (1) ◽  
pp. 40-46
Author(s):  
Vanitha Vasantharaghavan ◽  
Ravichandran Cingaram
Keyword(s):  
Zinc Oxide ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Accurate Determination ◽  
Voltammetric Determination ◽  
Carbon Electrode

Background: The Glassy Carbon Electrode (GCE) was modified with zinc oxide nanoparticles to enhance the electrocatalytic activity of the redox behavior of cefotaxime ion. ATOMIC Force Microscopy (AFM) photographic studies showed the nanorod like structure of the zinc oxide, which was coated uniformly on the electrode surface. Methods: The zinc oxide nanorod modified electrode was used as novel voltammetric determination of cefotaxime. The results of voltammetric behavior are satisfactory in the electro oxidation of cefotaxime, and exhibit considerable improvement compared to glassy carbon electrode. Results: Under the optimized experimental conditions, the ZnO nanorod modified electrode exhibit better linear dynamic range from 300 ppb to 700 ppb with lower limit of detection 200 ppb for the stripping voltammetric determination of cefotaxime. Conclusion: The pharmaceutical and clinical formulation of cefotaxime was successfully applied for accurate determination of trace amounts on ZnO nanomateials modified electrode.

scholarly journals Preparation and Application of Keggin Silicomolybdic acid Modified Electrode

2020 ◽  
Author(s):  
Miao Liu ◽  
Dong hui Li ◽  
Ming xuan Jia
Keyword(s):  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Photoelectron Spectroscopy ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
X Ray ◽  
Linear Relationships

Abstract An innovative method for the determination of isoniazid tablets is studied through electrochemical method for the modification of glassy carbon electrode (GCE). Polyoxomolybdate, with stable structures, has not been widely used for the determination of substance. In this study, the mentioned polyoxomolybdate was characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, X-ray diffraction (XRD), Atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), and used to modify the glassy carbon electrode (GCE). The electrochemical performance of the polyoxomolybdate@GCE was investigated with cyclic voltammetry (CV) and differential pulse voltammetry (DPV), compared with the unmodified electrode, the proposed polyoxomolybdate modified electrode exhibited strong electro-catalytic activities towards isoniazid (INH). Under the optimized conditions, there was linear relationships between the DPV peak currents and the concentrations in the range of 1 × 10 -7 g/L to 3 × 10 -7 g/L for INH (R 2 = 0.9979), with the limit of detection (LOD) of 0.024 μg/L (based on S/N = 3). The modified electrode has proper reproducibility (RSD < 5%), stability, response time (< 3 min) and lifetime (up to 6 days).

scholarly journals Simultaneous electrochemical sensing of dihydroxy benzene isomers at cost-effective allura red polymeric film modified glassy carbon electrode

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pattan-Siddappa Ganesh ◽  
Ganesh Shimoga ◽  
Seok-Han Lee ◽  
Sang-Youn Kim ◽  
Eno E. Ebenso
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Tap Water ◽  
Differential Pulse ◽  
Oxidation Potential ◽  
Electrochemical Sensing ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Allura Red

Abstract Background A simple and simultaneous electrochemical sensing platform was fabricated by electropolymerization of allura red on glassy carbon electrode (GCE) for the interference-free detection of dihydroxy benzene isomers. Methods The modified working electrode was characterized by electrochemical and field emission scanning electron microscopy methods. The modified electrode showed excellent electrocatalytic activity for the electrooxidation of catechol (CC) and hydroquinone (HQ) at physiological pH of 7.4 by cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. Results The effective split in the overlapped oxidation signal of CC and HQ was achieved in a binary mixture with peak to peak separation of 0.102 V and 0.103 V by CV and DPV techniques. The electrode kinetics was found to be adsorption-controlled. The oxidation potential directly depends on the pH of the buffer solution, and it witnessed the transfer of equal number of protons and electrons in the redox phenomenon. Conclusions The limit of detection (LOD) for CC and HQ was calculated to be 0.126 μM and 0.132 μM in the linear range of 0 to 80.0 μM and 0 to 110.0 μM, respectively, by ultra-sensitive DPV technique. The practical applicability of the proposed sensor was evaluated for tap water sample analysis, and good recovery rates were observed. Graphical abstract Electrocatalytic interaction of ALR/GCE with dihydroxy benzene isomers.

Differential pulse voltammetric determination of fenobucarb at the glassy carbon electrode, after its alkaline hydrolysis to a phenolic product

1997 ◽  
Vol 9 (12) ◽  
pp. 952-955 ◽  
Author(s):  
Agustina Guiberteau Cabanillas ◽  
Teresa Galeano Díaz ◽  
Francisco Salinas ◽  
Juan Manuel Ortiz ◽  
Jean Michel Kauffmann
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Alkaline Hydrolysis ◽  
Differential Pulse ◽  
Voltammetric Determination ◽  
Carbon Electrode

scholarly journals Determination of trace amounts of copper in iron and steel by differential pulse anodic stripping voltammetry at a glassy carbon electrode.

1998 ◽  
Vol 47 (5) ◽  
pp. 255-260 ◽  
Author(s):  
Tatsuhiko TANAKA ◽  
Manabu ADACHI ◽  
Takashi ISHIYAMA ◽  
Maki SATO ◽  
Akihiro ONO
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Iron And Steel ◽  
Anodic Stripping

scholarly journals The effect of tamoxifen on the electrochemical behavior of Bi+3/Bi on the glassy carbon electrode and its determination via differential pulse anodic stripping voltammetry

2019 ◽  
Vol 63 (1) ◽  
Author(s):  
Mehdi Jalali ◽  
Zeinab Deris Falahieh ◽  
Mohammad Alimoradi ◽  
Jalal Albadi ◽  
Ali Niazi
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Anodic Stripping Voltammetry ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Peak Height ◽  
Carbon Electrode

The electrochemical behavior of Bi+3 ions on the surface of a glassy carbon electrode, in acidic media and in the presence of tamoxifen, was investigated. Cyclic voltammetry, chronoamperometry, differential pulse voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy were used to find the probable mechanism contributing to the reduction of the peak height of bismuth oxidation with an increase in the concentration of tamoxifen. The obtained results show a slight interaction between the bismuth species and tamoxifen which co-deposit on the surface of glassy carbon electrode. Therefore, the reduction in the peak height of bismuth oxidation as a function of tamoxifen concentration was used to develop a new differential pulse anodic striping voltammetry method for determination of trace amount of tamoxifen. The effects of experimental parameters on the in situ DPASV of Bi+3 ions in the presence of tamoxifen shown the optimal conditions as: 2 mol L-1 H2SO4 (1% v v-1 MeOH), a deposition potential of -0.5 V, a deposition time of 60 s, and a glassy carbon electrode rotation rate of 300 rpm. The calibration curve was plotted in the range of 0.5 to 6 µg mL-1 and the limits of detection and quantitation were calculated to be 3.1 × 10-5 µg mL-1 and 1.0 × 10-4 µg mL-1, respectively. The mean, RSD, and relative bias for 0.5 µg mL-1 (n=5) were found to be 0.49 µg mL-1, 0.3%, and 2%, respectively. Finally, the proposed method was successfully used for the determination of tamoxifen in serum and pharmaceutical samples.

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