scholarly journals Polymethionine modified carbon nanotube sensor for sensitive and selective determination of L-tryptophan

2020 ◽  
Vol 10 (4) ◽  
pp. 305-315
Author(s):  
Nambudumada S. Prinith ◽  
Jamballi G. Manjunatha
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Phosphate Buffer Solution ◽  
Calibration Plot ◽  
Linear Segment ◽  
Current Signal ◽  
Buffer Solution ◽  
Detection Range ◽  
Selective Determination

The electrochemically initiated catalytic oxidation of amino acid L-tryptophan (L-TPN) in phosphate buffer solution has been scrutinized using highly conductive polymethionine modified carbon nanotube paste sensor (PMETCNTPS) through cyclic voltammetry (CV) technique. Compared to the bare carbon nanotube paste sensor (BCNTPS), PMETCNTPS exhibited a quantifiable current signal by CV method. PMETCNTPS was found sensitive to L-TPN concentrations within the linear segment of detection range 1.5 - 8.0×10-5 M. By employing the calibration plot, the detection limit was determined as 6.99×10-7 M. In addition, PMETCNTPS was successfully exploited and validated in determining L-TPN in the pharmaceutical supplement.

Selective determination of mefenamic acid in the presence of 1000-fold excess paracetamol and caffeine using a multiwalled carbon nanotube–polymer composite electrode

2015 ◽  
Vol 7 (8) ◽  
pp. 3506-3511 ◽  
Author(s):  
K. Rajalakshmi ◽  
S. Abraham John
Keyword(s):  
Carbon Nanotube ◽  
Polymer Composite ◽  
Mefenamic Acid ◽  
Phosphate Buffer Solution ◽  
Multiwalled Carbon Nanotube ◽  
Buffer Solution ◽  
Solution Ph ◽  
Multiwalled Carbon ◽  
Selective Determination

This article describes the selective and sensitive determination of mefenamic acid (MA) using a carboxylated multiwalled carbon nanotube nanostructured conducting polymer composite modified glassy carbon electrode in 0.2 M phosphate buffer solution (pH 7.2).

Fabrication of Graphene/Carbon Nanotube Composite Modified Electrode for Selective and Sensitive Determination of Uric Acid

2013 ◽  
Vol 641-642 ◽  
pp. 562-565
Author(s):  
Zheng Xiao Liu ◽  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Uric Acid ◽  
Carbon Nanotube ◽  
Modified Electrode ◽  
Phosphate Buffer Solution ◽  
Carbon Electrode ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Carbon Nanotube Composite

A novel composite was firstly synthesized by compositing graphenes (G) and carbon nanotubes (CNTs) and then a new composite modified electrode (G/CNTs/GCE) was prepared by coating the resulting composite on the surface of the glassy carbon electrode (GCE). The composite modified electrode G/CNTs/GCE showed great electrochemical activities which were studied by sensitive determining the electrochemistry behaviors of uric acid (UA). It revealed when the concentration range of UA changed from 1×10-7 mol/L to 1×10-3 mol/L, the peak currents had linear relationship with the concentration of UA in the phosphate buffer solution (PBS) which the value of pH is 7.0. And the linear equation is ip (μA) = 21.55C+28.94 (C: mmol/L), with the related coefficient 0.9964.

scholarly journals Poly (DL-valine) electro-polymerized carbon nanotube paste sensor for determination of antihistamine drug cetirizine

2020 ◽  
Author(s):  
Tigari Girish ◽  
Jamballi G. Manjunatha ◽  
Pemmatte A. Pushpanjali ◽  
Nambudumada S. Prinith ◽  
Doddarasinakere K. Ravishankar ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Organic Molecules ◽  
Phosphate Buffer Solution ◽  
Multiwalled Carbon Nanotube ◽  
Buffer Solution ◽  
Solution Ph ◽  
Multiwalled Carbon ◽  
Accumulation Time ◽  
Antihistamine Drug

Poly (DL-valine) modified multiwalled carbon nanotube paste sensor (PVLMCNTPS) was prepared by electro-polymerization route. PVLMCNTPS and bare multiwalled carbon nanotube paste sensor (BMCNTPS) morphologies and sensing properties for cetirizine (CTZ) were confirmed through a field emission scanning electron microscope (FE-SEM) and electrochemical studies, respectively. In contrast to BMCNTPS, PVLMCNTPS surface composite creates an electrocatalytic impact on the oxidation of CTZ. PVLMCNTPS properties were optimized using parameters such as accumulation time, number of polymerization cycles, solution pH, and scan rate. The optimized PVLMCNTPS was applied for the determination of cetirizine in 0.1 M phosphate buffer solution (PBS) of pH 7.0, using cyclic voltammetry (CV). It is shown that PVLMCNTPS provided analytical linearity from 2.0 to 80 µM, with a detection limit of 0.11 µM for CTZ determination. PVLMCNTPS is found highly selective for CTZ in presence of some interfering organic molecules. The stable and selective PVLMCNTPS was applied for CTZ determination in pharmaceutical pills with satisfactory results.

scholarly journals Single-Walled-Carbon-Nanotube-Modified Pyrolytic Graphite Electrode Used as a Simple Sensor for the Determination of Salbutamol in Urine

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Rajendra N. Goyal ◽  
Sunita Bishnoi ◽  
Bharati Agrawal
Keyword(s):  
Carbon Nanotube ◽  
Human Urine ◽  
Graphite Electrode ◽  
Pyrolytic Graphite ◽  
Phosphate Buffer Solution ◽  
Calibration Plot ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Pyrolytic Graphite Electrode

A fast and sensitive voltammetric method has been proposed for the determination of salbutamol at single-walled-carbon-nanotube-modified edge-plane pyrolytic graphite electrode (SWNT/EPPGE) in human urine. The electrochemical response of salbutamol was determined by square wave voltammetry (SWV) in phosphate buffer solution (PBS) at physiological pH 7.2. The modified electrode showed improved voltammetric response towards the oxidation of salbutamol, and a well-defined anodic peak was observed at~600 mV with enhanced peak current in comparison to the bare electrode. Linear calibration plot using SWNT/EPPGE was obtained in the concentration range of 50 to 2500 ngml-1with sensitivity and detection limit of 2.15 nA/ngml-1and 4.31 ngml-1, respectively. The developed method has been successfully applied for the determination of salbutamol in commercial preparations and human body fluids. Fast analysis of salbutamol in human urine makes the proposed method of great interest for doping control purposes at the site of competitive games.

Non-enzymatic determination of purine nucleotides using a carbon dot modified glassy carbon electrode

2019 ◽  
Vol 11 (30) ◽  
pp. 3866-3873 ◽  
Author(s):  
R. Karthikeyan ◽  
D. James Nelson ◽  
S. Abraham John
Keyword(s):  
Glassy Carbon ◽  
Low Cost ◽  
Phosphate Buffer Solution ◽  
Purine Nucleotides ◽  
Buffer Solution ◽  
Solution Ph ◽  
Carbon Dot ◽  
Enzymatic Determination ◽  
Sensitive Determination

Selective and sensitive determination of one of the purine nucleotides, inosine (INO) using a low cost carbon dot (CD) modified glassy carbon (GC) electrode in 0.2 M phosphate buffer solution (pH 7.2) was demonstrated in this paper.

Development and Validation of HPLC Determination of related Substances in A Novel Anticonvulsant agent Epimidin

2021 ◽  
pp. 3223-3231
Author(s):  
Hanna I. Severina ◽  
Svitlana M. Gubar ◽  
Ivan V. Bezruk ◽  
Anna S. Materiienko ◽  
Liudas Ivanauskas ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Phosphate Buffer Solution ◽  
Anticonvulsant Drug ◽  
Strong Acid ◽  
Gradient Elution ◽  
Stress Conditions ◽  
Drug Candidate ◽  
Buffer Solution ◽  
Related Substances

1-(4-methoxyphenyl)-5-[2-[4-(4-methoxyphenyl)piperazin-1-yl]-2-oxo-ethyl]pyrazolo[3,4-d]pyrimidin-4-one has been reported as a promising new anticonvulsant drug candidate with a code name “Epimidin”. A new HPLC method for the related substances determination of potential active pharmaceutical ingredient has been developed and validated. The method uses ACE C18 column (250x4.6mm, 5µm) and gradient elution. Mobile phase consisted of a mixture of methanol R (mobile phase A) and phosphate buffer solution with triethanolamine, adjusted to pH 7.0 (mobile phase B). During the analysis, the ratio of mobile phases was changing according to a gradient mode at a flow rate of 1ml/min. The DAD detection was set at 240nm. The method was validated according to the ICH guidelines and requirements of State Pharmacopoeia of Ukraine. Drug substance was thoroughly explored for stability assessments under various stress conditions such as high temperature, as well as the influence of strong acid and base and oxidizing agents. The obtained solutions were analyzed by HPLC and LC/MS. It has been shown that the substance Epimidin was not resistant to the action of peroxide, alkali and acid decomposition – the mentioned stress conditions lead to the formation of unidentified impurities.

scholarly journals Carvacrol electrochemical reaction characteristics on screen printed electrode modified with La2O3/Co3O4 nanocomposite

2019 ◽  
Vol 9 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Sayed Zia Mohammadi ◽  
Hadi Beitollahi ◽  
Tahereh Rohani ◽  
Hossein Allahabadi
Keyword(s):  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Co3o4 Nanoparticles ◽  
Electrochemical Characteristics ◽  
Screen Printed Electrode ◽  
Buffer Solution ◽  
Voltammetric Techniques ◽  
Screen Printed

Electrochemical characteristics of carvacrol were investigated on a screen-printed electrode (SPE) modified with La2O3/Co3O4 nanocomposite by using voltammetric techniques, which displayed a well-defined peak for sensitive carvacrol determination in phosphate buffer solution (PBS) at pH 7.0. La2O3/Co3O4 nanoparticles demonstrated suitable catalytic activity for carvacrol determination by differential pulse voltammetry (DPV) technique. Besides, determination of carvacrol in a real samples was recognized in the light of electrochemical findings and a validated voltammetric technique for quantitative analysis of carvacrol in a real formulation was proposed. The DPV peak currents were found to be linear in the concentration range of 10.0 to 800.0 μM. The limit of detection (LOD) was found to be 1.0 μM.

Selective Determination of Chloride and Bromide Ions in Serum by Cyclic Voltammetry

1996 ◽  
Vol 240 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Kensuke Arai ◽  
Fumiyo Kusu ◽  
Naohito Noguchi ◽  
Kiyoko Takamura ◽  
Hisao Osawa
Keyword(s):  
Cyclic Voltammetry ◽  
Selective Determination ◽  
Bromide Ions
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