scholarly journals Selective Electrochemical Detection of Epinephrine Using Gold Nanoporous Film

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Dina M. Fouad ◽  
Waleed A. El-Said
Keyword(s):  
Uric Acid ◽  
Gold Electrode ◽  
High Selectivity ◽  
High Surface ◽  
High Surface Area ◽  
Nanoporous Materials ◽  
Selective Determination ◽  
Sensing Applications ◽  
Other Substances

Epinephrine (EP) is one of the important catecholamine neurotransmitters that play an important role in the mammalian central nervous system. Therefore, it is necessary to determine the change of its concentrations. Nanoporous materials have wide applications that include catalysis, energy storages, environmental pollution control, wastewater treatment, and sensing applications. These unique properties could be attributable to their high surface area, a large pore volume, and uniform pore sizes. A gold nanoporous layer modified gold electrode was prepared and applied for the selective determination of epinephrine neurotransmitter at low concentration in the presence of several other substances including ascorbic acid (AA) and uric acid (UA). The constructed electrode was characterized using scanning electron microscopy and cyclic voltammetry. The resulting electrode showed a selective detection of epinephrine with the interferences of dopamine and uric acid over a wide linear range (from 50 μM to 1 mM). The coverage of gold nanoporous on the surface of gold electrode represents a promising electrochemical sensor with high selectivity and sensitivity.

Selective determination of uric acid in the presence of ascorbic acid using a penicillamine self-assembled gold electrode

2006 ◽  
Vol 158 (1-2) ◽  
pp. 73-78 ◽  
Author(s):  
Liang Wang ◽  
Jun Yue Bai ◽  
Peng Fei Huang ◽  
Hong Jing Wang ◽  
Xiao Wei Wu ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Uric Acid ◽  
Gold Electrode ◽  
Selective Determination ◽  
Self Assembled

Selective Determination of Entecavir in the Presence of Its Oxidative Degradate by Spectrophotometric and Chromatographic Methods

2021 ◽  
Author(s):  
Heba M El-Sayed ◽  
Laila E Abdel Fattah ◽  
Hisham E Abdellatef ◽  
Maha A Hegazy ◽  
Mai M Abd El-Aziz
Keyword(s):  
High Selectivity ◽  
Oxidative Degradation ◽  
Hplc Method ◽  
Peak Amplitude ◽  
Quality Analysis ◽  
Official Method ◽  
Selective Determination ◽  
Significant Difference ◽  
Development And Validation

Abstract Background Entecavir (ENT) is an antiretroviral agent prescribed for treatment of HBV and HIV. Objective Development and validation of three simple, sensitive, selective, and precise methods for determination of ENT in presence of its oxidative degradation product (ENT deg.). Methods The first method was based on second derivative (D2) spectrophotometry through measuring the peak amplitude of D2 spectra at 293.6 nm. The second one is mean centering of the ratio spectra (MCR), which allowed measuring the peak amplitude at 280.0 nm. While the third method was HPLC; where ENT was separated from ENT deg. using Zobrax C18column and methanol: water (30:70, v/v), pH 3 as a mobile phase. The three developed methods were validated according to ICH guidelines. Results Linearity range of ENT was 5.00–50.00 μg/mL for both D2and MCR. However, higher sensitivity was achieved using HPLC (1.00–50.00 μg/mL). Accuracy of ENT were 100.60%±0.547, 101.55%±1.2071 and 100.61%±1.207 for D2, MCR and HPLC methods, respectively, and precision was within 1.280. Conclusions The developed methods were successfully applied for the determination of ENT in Tecavir® tablets without interference from ENT deg. They showed no significant difference compared with the official method as well as they could be applied in the quality analysis of ENT with high selectivity, accuracy, and precision. Highlights ENT was quantified using two spectrophotometric (D2 and MCR) methods and an HPLC method in presence of ENT deg. The proposed methods were applied to analysis of ENT tablets with high selectivity, sensitivity, and accuracy.

Lawsone Derived Zn (II) and Fe (III) Metal Organic Frameworks with pH Dependent Emission for Controlled Drug Delivery

2021 ◽  
Author(s):  
Sirajunnisa P ◽  
Liz Hannah George ◽  
Narayanapillai Manoj ◽  
Prathapan S ◽  
G.S. Sailaja
Keyword(s):  
Drug Delivery ◽  
Porous Structure ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
High Surface Area ◽  
Controlled Drug Delivery ◽  
Sensing Applications ◽  
Porous Carriers ◽  
Metal Organic ◽  
Ph Dependent

Fluorescent biocompatible porous carriers have been investigated as suitable probes for drug delivery and sensing applications owing to their intrinsic fluorescence and high surface area originating from their porous structure...

Sensitive and selective determination of hydroxychloroquine in the presence of uric acid using a new nanostructure self-assembled monolayer modified electrode: optimization by multivariate data analysis

The Analyst ◽  
2014 ◽  
Vol 139 (16) ◽  
pp. 4064-4072 ◽  
Author(s):  
Asma Khoobi ◽  
Sayed Mehdi Ghoreishi ◽  
Mohsen Behpour
Keyword(s):  
Uric Acid ◽  
Self Assembly ◽  
Multivariate Data Analysis ◽  
Covalent Modification ◽  
Carbon Electrode ◽  
Self Assembled Monolayer ◽  
Selective Determination ◽  
Highly Sensitive ◽  
Electrochemical Nanosensor

A highly sensitive electrochemical nanosensor was developed using covalent modification of a glassy carbon electrode (GCE) by self-assembly of a novel Schiff base.

Self-Assembled Submonolayer of β-Cyclodextrins on Gold Electrode for the Selective Determination of 4-Aminobiphenyl

2011 ◽  
Vol 23 (12) ◽  
pp. 2862-2869 ◽  
Author(s):  
Idania Carrillo ◽  
Carmen Quintana ◽  
Ana M. Esteva ◽  
Lucas Hernández ◽  
Pedro Hernández
Keyword(s):  
Gold Electrode ◽  
Selective Determination ◽  
Self Assembled

Improved automated kinetic determination of uric acid in serum by use of uricase/catalase/aldehyde dehydrogenase.

1979 ◽  
Vol 25 (4) ◽  
pp. 619-621 ◽  
Author(s):  
K Bartl ◽  
M Brandhuber ◽  
J Ziegenhorn
Keyword(s):  
Uric Acid ◽  
Aldehyde Dehydrogenase ◽  
Alcohol Dehydrogenase Isoenzymes ◽  
Kinetic Determination ◽  
Enzymatic Determination ◽  
Other Substances ◽  
Inhibitor System ◽  
Uric Acid Determination ◽  
Acid Determination

Abstract The enzymatic determination of serum uric acid by use of uricase, catalase, and aldehyde dehydrogenase according to Haeckel [J. Clin. Chem. Clin Biochem. 14, 101 (1976)] showed interferences from ethanol-converting enzymes, which are present in some patients' sera. We have identified these enzymes as alcohol dehydrogenase isoenzymes. Among other substances, a mixture of pyrazole and oxalate can be used to eliminate these interferences. This inhibitor system gives good results when used in the automated kinetic uric acid determination, as is shown by a comparison with the manual assay for uric acid according to Kageyama [Clin. Chim. Acta 31, 421 (1971)].

scholarly journals Dipsticks with Reflectometric Readout of an NIR Dye for Determination of Biogenic Amines

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 99
Author(s):  
Sarah N. Mobarez ◽  
Nongnoot Wongkaew ◽  
Marcel Simsek ◽  
Antje J. Baeumner ◽  
Axel Duerkop
Keyword(s):  
Biogenic Amines ◽  
Indium Tin Oxide ◽  
Near Infrared ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Sample Pretreatment ◽  
Primary Amines ◽  
Nir Dye

Electrospun nanofibers (ENFs) are remarkable analytical tools for quantitative analysis since they are inexpensive, easily produced in uniform homogenous mats, and provide a high surface area-to-volume ratio. Taking advantage of these characteristics, a near-infrared (NIR)-dye was doped as chemosensor into ENFs of about 500 nm in diameter electrospun into 50 µm thick mats on indium tin oxide (ITO) supports. The mats were made of cellulose acetate (CA) and used as a sensor layer on optical dipsticks for the determination of biogenic amines (BAs) in food. The ENFs contained the chromogenic amine-reactive chameleon dye S0378 which is green and turns blue upon formation of a dye-BA conjugate. This SN1-reaction of the S0378 dye with various BAs was monitored by reflectance measurements at 635 nm where the intrinsic absorption of biological material is low. The difference of the reflectance before and after the reaction is proportional to BA levels from 0.04–1 mM. The LODs are in the range from 0.03–0.09 mM, concentrations that can induce food poisoning but are not recognized by the human nose. The calibration plots of histamine, putrescine, spermidine, and tyramine are very similar and suggesting the use of the dipsticks to monitor the total sample BA content. Furthermore, the dipsticks are selective to primary amines (both mono- and diamines) and show low interference towards most nucleophiles. A minute interference of proteins in real samples can be overcome by appropriate sample pretreatment. Hence, the ageing of seafood samples could be monitored via their total BA content which rose up to 21.7 ± 3.2 µmol/g over six days of storage. This demonstrates that optically doped NFs represent viable sensor and transducer materials for food analysis with dipsticks.

A one-step electrochemically reduced graphene oxide based sensor for sensitive voltammetric determination of furfural in milk products

2021 ◽  
Vol 13 (1) ◽  
pp. 56-63
Author(s):  
Qiuqiu Wang ◽  
Juanhua Zhang ◽  
Yanbo Xu ◽  
Yingyi Wang ◽  
Liang Wu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Milk Products ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide ◽  
One Step ◽  
Dairy Milk

One-step electrochemically reduced graphene oxide with high surface area and improved electron transfer kinetics shows great performances in the determination of furfural in dairy milk.

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