scholarly journals Enzymatic Electroanalytical Biosensor Based on Maramiellus colocasiae Fungus for Detection of Phytomarkers in Infusions and Green Tea Kombucha

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 91
Author(s):  
Érica A. Batista ◽  
Giovanna N. M. Silva ◽  
Livia F. Sgobbi ◽  
Fabio B. Machado ◽  
Isaac Y. Macedo ◽  
...  
Keyword(s):  
Detection Limit ◽  
Gallic Acid ◽  
Green Tea ◽  
High Performance ◽  
Differential Pulse ◽  
Linear Range ◽  
Crude Enzyme Extract ◽  
Quantification Limit ◽  
The City

In this work, we developed an enzymatic voltammetric biosensor for the determination of catechin and gallic acid in green tea and kombucha samples. The differential pulse voltammetry (DPV) methodology was optimized regarding the amount of crude enzyme extract, incubation time in the presence of the substrates, optimal pH, reuse of the biosensor, and storage time. Samples of green tea and kombucha were purchased in local markets in the city of Goiânia-GO, Brazil. High performance liquid chromatography (HPLC) and Folin-Ciocalteu spectrophotometric techniques were performed for the comparison of the analytical methods employed. In addition, two calibration curves were made, one for catechin with a linear range from 1 to 60 µM (I = −0.152 * (catechin) − 1.846), with a detection limit of 0.12 µM and a quantification limit of 0.38 µM and one for gallic acid with a linear range from 3 to 60 µM (I = −0.0415 * (gallic acid) − 0.0572), with a detection limit of 0.14 µM and a quantification limit of 0.42 µM. The proposed biosensor was efficient in the determination of phenolic compounds in green tea.

scholarly journals Validation of High Performance Liquid Chromatography Methods for Determination of Meloxicam and Tenoxicam from Transdermal Therapeutic Systems

2017 ◽  
Vol 63 (4) ◽  
pp. 178-182 ◽  
Author(s):  
Paula Antonoaea ◽  
Anca Gabriela Cârje ◽  
Adriana Ciurba ◽  
Nicoleta Todoran ◽  
Alexandru Robert Vlad ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Detection Limit ◽  
High Performance ◽  
Hydroxypropyl Methylcellulose ◽  
Active Pharmaceutical Ingredient ◽  
Performance Criteria ◽  
Quantification Limit ◽  
Transdermal Patches ◽  
Evaporation Technique

AbstractObjective: The aim of this study was to develop and validate two HPLC methods for the quantification of meloxicam and tenoxicam from transdermal therapeutic systems.Methods: Based on 1.0% hydroxypropyl methylcellulose 15000, transdermal patches containing meloxicam or tenoxicam were prepared by solvent evaporation technique. Analytical performances of the HPLC methods for the quantification of meloxicam and tenoxicam from such systems were assessed in terms of specificity, linearity, detection limit, quantification limit, recovery and precision.Results and discussion: The linearity of the method was assessed through a calibration curve in the 1.0 - 75.0 μg∙mL−1concentration range, with a regression coefficient higher than 0.999. The detection limit and the quantification limit were found to be 0.46 μg∙mL−1and 1.39 μg∙mL−1, for meloxicam; and 0.88 μg∙mL−1, respectively 2.64 μg∙mL−1for tenoxicam. According to the European Pharmacopeia 5.0 the mean recovery was found to be between 75% and 125%. As performance criteria for precision was used the RSD% which were lower than 2.0% for both methods.Conclusions: The proposed liquid chromatography methods provide selective, linear and precise results for the quantification of meloxicam and tenoxicam from transdermal therapeutic systems. The presence of a single peak in the chromatograms of the analyzed transdermal patches with meloxicam or tenoxicam, certify the successful determination of the active pharmaceutical ingredient in the prepared patches.

scholarly journals Development of a Method for a Sensitive Simultaneous Determination of Dopamine and Paracetamol in Biological Samples and Pharmaceutical Preparations

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Ali Babaei ◽  
Aliyeh Dehdashti ◽  
Mohammad Afrasiabi
Keyword(s):  
Detection Limit ◽  
Modified Electrode ◽  
Pharmaceutical Preparation ◽  
Pharmaceutical Preparations ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Linear Range ◽  
Multiwalled Carbon ◽  
Excellent Stability

A chemically modified electrode is constructed based on multiwalled carbon nanotube—modified glassy carbon electrode (MWCNTs/GCE). The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronoamperometry (CA) methods. Application of DPV method showed wide linear range of DA from 1 μM to 540 μM and a detection limit of 0.098 μM (S/N=3). The linear range of PAR of 3 μM to 300 μM and a detection limit of 0.15 μM, were obtained. The modified electrode showed electrochemical responses with high sensitivity, high selectivity, and excellent stability for DA and PAR determination at optimal conditions, which makes it a suitable sensor for simultaneous submicromolar detection of DA and PAR in solutions. The analytical performance of this sensor has been evaluated for detection of DA and PAR in human serum, human urine, and pharmaceutical preparation with satisfactory results.

The Dtermination of Paracetamol by HPLC Validation of the Method and Application on Serum Samples

2018 ◽  
Vol 69 (3) ◽  
pp. 627-631 ◽  
Author(s):  
Viorica Ohriac (Popa) ◽  
Diana Cimpoesu ◽  
Adrian Florin Spac ◽  
Paul Nedelea ◽  
Voichita Lazureanu ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Hplc Analysis ◽  
Emotional Experience ◽  
Optimum Conditions ◽  
Serum Samples ◽  
Liquid Chromatograph ◽  
Mobile Phase Flow Rate ◽  
Quantification Limit

Pain is defined as a disagreeable sensory and emotional experience related to a tissue or potential lesion. Paracetamol (Acetaminophen) is the most used non-morphine analgesic. For the determination of paracetamol we developed and validated the high performance liquid chromatography (HPLC) analysis using a Dionex Ultimate 3000 liquid chromatograph equipped with a multidimensional detector. After determining the optimum conditions of analysis (80/20 water / acetonitrile mobile phase, flow rate 1.0 mL / min, detection wavelength 245 nm) we validated the method following the following parameters: linearity of response function, linearity of results, limit (LD = 0.66 mg / mL) and quantification limit (LQ = 2.00 mg / mL), and precision. The method of determining paracetamol by HPLC was applied to 30 samples of serum collected from patients who had pain and were treated with paracetamol.

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.

Preparation of yolk–shell structured Ag@Cu particles and their application in high performance electrochemical sensing of p-aminobenzoic acid

2019 ◽  
Vol 97 (2) ◽  
pp. 140-146
Author(s):  
Tian Gan ◽  
Zhikai Wang ◽  
Mengru Chen ◽  
Wanqiu Fu ◽  
Haibo Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Electrochemical Impedance ◽  
High Sensitivity ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
High Catalytic Activity ◽  
Aminobenzoic Acid ◽  
Transmission Electron

In this work, the Ag@Cu particles with yolk–shell nanostructure was prepared by facile solvothermal method, which was modified on glassy carbon electrode (GCE) to fabricate electrochemical sensor for the convenient and fast determination of p-aminobenzoic acid (PABA). The surface morphology and electrochemical properties of the as-prepared Ag@Cu nanocomposite modified electrode were characterized by scanning electron microscopy, transmission electron microscopy, chronocoulometry, and electrochemical impedance spectroscopy. Further, the electrochemical sensing of PABA was performed on the Ag@Cu/GCE using cyclic voltammetry and differential pulse voltammetry techniques, showing high catalytic activity. Under the optimal conditions, the sensor exhibited a wide linear range, high sensitivity, and low detection limit of 0.315 μmol/L for PABA. The developed sensor was also successfully applied for PABA detection in anesthetic and cosmetics with satisfactory results.

scholarly journals QUANTITATIVE DETERMINATION OF PHENOL CARBOXYLIC ACIDS IN POMEGRANATE FRUIT PULP BY THE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH ULTRAVIOLET DETECTION

2019 ◽  
Vol 12 (1) ◽  
pp. 548
Author(s):  
Ruben Ashotovich Pogosyan ◽  
Olga Vladimirovna Nesterova ◽  
Dmitry Olegovich Bokov ◽  
Irina Alexandrovna Samylina
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phenolic Compounds ◽  
Quantitative Determination ◽  
Gallic Acid ◽  
Carboxylic Acids ◽  
High Performance ◽  
Fruit Pulp ◽  
Pomegranate Fruit

Objective: Pomegranate (Punica granatum L.) is a broadly used plant possessing a wide range of medicinal properties. In this research, we have mainly focused on the investigation of phenolic compounds of pomegranate fruit pulp (PFP).Methods: Fresh fruits of “Çəhrayı Gülöyşə,” “Kizil-anor,” and pomegranate varietal mixture were used as samples. High-performance liquid chromatography-ultraviolet (HPLC-UV) analysis of phenol carboxylic acids was performed with metal column Kromasil® C18 (4.6×250 mm, particle size 5 μm) and the acetonitrile-water-concentrated acid phosphoric system (400:600:5) under isocratic elution conditions (flow rate of 0.5 ml/min). Detection was carried out using a UV detector “GILSTON” UV/Visible model 151 at a wavelength of 280 nm.Results and Discussion: As a result of our research, we proposed chromatographic conditions for the separation of phenolic compounds, the conditions for sample preparation of PFP. Procedure for determination of phenolic carboxylic acids total content in terms of gallic acid by HPLC-UV method was developed. According to the obtained data, the content of phenolic carboxylic acids should be at least 0.7%.Conclusion: Procedure for the quantitative determination of gallic acid using the HPLC-UV method was developed. This method which can be used in the standardization of new medicinal plant raw materials - PFP, as well as extract preparations based on it in the future.

scholarly journals QUANTITATIVE DETERMINATION OF PHENOL CARBOXYLIC ACIDS IN POMEGRANATE FRUIT PULP BY THE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH ULTRAVIOLET DETECTION

2019 ◽  
Vol 12 (1) ◽  
pp. 548
Author(s):  
Ruben Ashotovich Pogosyan ◽  
Olga Vladimirovna Nesterova ◽  
Dmitry Olegovich Bokov ◽  
Irina Alexandrovna Samylina
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phenolic Compounds ◽  
Quantitative Determination ◽  
Gallic Acid ◽  
Carboxylic Acids ◽  
High Performance ◽  
Fruit Pulp ◽  
Pomegranate Fruit

Objective: Pomegranate (Punica granatum L.) is a broadly used plant possessing a wide range of medicinal properties. In this research, we have mainly focused on the investigation of phenolic compounds of pomegranate fruit pulp (PFP).Methods: Fresh fruits of “Çəhrayı Gülöyşə,” “Kizil-anor,” and pomegranate varietal mixture were used as samples. High-performance liquid chromatography-ultraviolet (HPLC-UV) analysis of phenol carboxylic acids was performed with metal column Kromasil® C18 (4.6×250 mm, particle size 5 μm) and the acetonitrile-water-concentrated acid phosphoric system (400:600:5) under isocratic elution conditions (flow rate of 0.5 ml/min). Detection was carried out using a UV detector “GILSTON” UV/Visible model 151 at a wavelength of 280 nm.Results and Discussion: As a result of our research, we proposed chromatographic conditions for the separation of phenolic compounds, the conditions for sample preparation of PFP. Procedure for determination of phenolic carboxylic acids total content in terms of gallic acid by HPLC-UV method was developed. According to the obtained data, the content of phenolic carboxylic acids should be at least 0.7%.Conclusion: Procedure for the quantitative determination of gallic acid using the HPLC-UV method was developed. This method which can be used in the standardization of new medicinal plant raw materials - PFP, as well as extract preparations based on it in the future.

scholarly journals Selective Determination of Iron(III) in Sea Water by Gold Nanoparticles Self-assembled with N-carboxyl- L-cysteine

2014 ◽  
Vol 17 (1) ◽  
pp. 001-004 ◽  
Author(s):  
Benzhi Liu ◽  
Min Wang
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Sea Water ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Operational Parameters ◽  
Selective Determination ◽  
Self Assembled ◽  
Optimized Conditions

Application of gold nanoparticles self-assembled with N-carboxyl- L-cysteine for the determination of iron(III) was investigated. Differential pulse adsorptive stripping voltammetry was used to detect iron(III). Various operational parameters were investigated and discussed in terms of their effects on the measurement signals. A linear range from 0.1 nM to 1.8 nM with a detection limit of 0.03 nMwas obtained under optimized conditions. The applicability of the method was successfully tested by determination of iron(III) in sea water samples.

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