scholarly journals Simple and Cost-Effective Electrochemical Method for Norepinephrine Determination Based on Carbon Dots and Tyrosinase

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4567 ◽  
Author(s):  
Sylwia Baluta ◽  
Anna Lesiak ◽  
Joanna Cabaj
Keyword(s):  
Electrochemical Method ◽  
Gold Electrode ◽  
High Selectivity ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Differential Pulse ◽  
Modern Medicine ◽  
Limit Of Quantification ◽  
Voltammetric Techniques ◽  
Pulse Voltammetry

Although neurotransmitters are present in human serum at the nM level, any dysfunction of the catecholamines concentration may lead to numerous serious health problems. Due to this fact, rapid and sensitive catecholamines detection is extremely important in modern medicine. However, there is no device that would measure the concentration of these compounds in body fluids. The main goal of the present study is to design a simple as possible, cost-effective new biosensor-based system for the detection of neurotransmitters, using nontoxic reagents. The miniature Au-E biosensor was designed and constructed through the immobilization of tyrosinase on an electroactive layer of cysteamine and carbon nanoparticles covering the gold electrode. This sensing arrangement utilized the catalytic oxidation of norepinephrine (NE) to NE quinone, measured with voltammetric techniques: cyclic voltammetry and differential pulse voltammetry. The prepared bio-system exhibited good parameters: a broad linear range (1–200 μM), limit of detection equal to 196 nM, limit of quantification equal to 312 nM, and high selectivity and sensitivity. It is noteworthy that described method was successfully applied for NE determination in real samples.

scholarly journals Supramolecular assemblies of carbon nanocoils and tetraphenylporphyrin derivatives for sensing of catechol and hydroquinone in aqueous solution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syeda Aqsa Batool Bukhari ◽  
Habib Nasir ◽  
Lujun Pan ◽  
Mehroz Tasawar ◽  
Manzar Sohail ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Linear Trend ◽  
Differential Pulse ◽  
Peak Potential ◽  
Limit Of Quantification ◽  
Efficient Detection ◽  
Good Repeatability ◽  
Ft Ir ◽  
Pulse Voltammetry

AbstractNon-enzymatic electrochemical detection of catechol (CC) and hydroquinone (HQ), the xenobiotic pollutants, was carried out at the surface of novel carbon nanocoils/zinc-tetraphenylporphyrin (CNCs/Zn-TPP) nanocomposite supported on glassy carbon electrode. The synergistic effect of chemoresponsive activity of Zn-TPP and a large surface area and electron transfer ability of CNCs lead to efficient detection of CC and HQ. The nanocomposite was characterized by using FT-IR, UV/vis. spectrophotometer, SEM and energy dispersive X-ray spectroscopy (EDS). Cyclic voltammetry, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy were used for the electrochemical studies. CNCs/Zn-TPP/GCE nanosensor displayed a limit of detection (LOD), limit of quantification (LOQ) and sensitivity for catechol as 0.9 µM, 3.1 µM and 0.48 µA µM−1 cm−2, respectively in a concentration range of 25–1500 µM. Similarly, a linear trend in the concentration of hydroquinone detection was observed between 25 and 1500 µM with an LOD, LOQ and sensitivity of 1.5 µM, 5.1 µM and 0.35 µA µM−1 cm−2, respectively. DPV of binary mixture pictured well resolved peaks with anodic peak potential difference, ∆Epa(CC-HQ), of 110 mV showing efficient sensing of CC and HQ. The developed nanosensor exhibits stability for up to 30 days, better selectivity and good repeatability for eight measurements (4.5% for CC and 5.4% for HQ).

scholarly journals An efficient electrochemical sensing of hazardous catechol and hydroquinone at direct green 6 decorated carbon paste electrode

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. Chetankumar ◽  
B. E. Kumara Swamy ◽  
S. C. Sharma ◽  
S. A. Hariprasad
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Tap Water ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Carbon Paste ◽  
Pulse Voltammetry ◽  
Two Peaks ◽  
Paste Electrode ◽  
Scanning Electron

AbstractIn this proposed work, direct green 6 (DG6) decorated carbon paste electrode (CPE) was fabricated for the efficient simultaneous and individual sensing of catechol (CA) and hydroquinone (HY). Electrochemical deeds of the CA and HY were carried out by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at poly-DG6-modfied carbon paste electrode (Po-DG6-MCPE). Using scanning electron microscopy (SEM) studied the surface property of unmodified CPE (UCPE) and Po-DG6-MCPE. The decorated sensor displayed admirable electrocatalytic performance with fine stability, reproducibility, selectivity, low limit of detection (LLOD) for HY (0.11 μM) and CC (0.09 μM) and sensor process was originated to be adsorption-controlled phenomena. The Po-DG6-MCPE sensor exhibits well separated two peaks for HY and CA in CV and DPV analysis with potential difference of 0.098 V. Subsequently, the sensor was practically applied for the analysis in tap water and it consistent in-between for CA 93.25–100.16% and for HY 97.25–99.87% respectively.

scholarly journals Surface-Enhanced Oxidation and Determination of Isothipendyl Hydrochloride at an Electrochemical Sensing Film Constructed by Multiwalled Carbon Nanotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
S. N. Prashanth ◽  
Shankara S. Kalanur ◽  
Nagappa L. Teradal ◽  
J. Seetharamappa
Keyword(s):  
Limit Of Detection ◽  
Biological Fluids ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Good Precision ◽  
Multiwalled Carbon ◽  
Limit Of Quantification ◽  
Surface Enhanced ◽  
Ph Range

The electrochemical behavior of isothipendyl hydrochloride (IPH) was investigated at bare and multiwalled-carbon-nanotube modified glassy carbon electrode (MWCNT-GCE). IPH (55 μM) showed two oxidation peaks in Britton-Robinson (BR) buffer of pH 7.0. The oxidation process of IPH was observed to be irreversible over the pH range of 2.5–9.0. The influence of pH, scan rate, and concentration of the drug on anodic peak was studied. A differential pulse voltammetric method with good precision and accuracy was developed for the determination of IPH in pure and biological fluids. The peak current was found to be linearly dependent on the concentration of IPH in the range of 1.25–55 μM. The values of limit of detection and limit of quantification were noticed to be 0.284 and 0.949 μM, respectively.

scholarly journals Sandwich Electrochemical Immunosensor for Early Detection of Tuberculosis Based on Graphene/Polyaniline-Modified Screen-Printed Gold Electrode

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3926 ◽  
Author(s):  
Umi Mohd Azmi ◽  
Nor Yusof ◽  
Norzila Kusnin ◽  
Jaafar Abdullah ◽  
Siti Suraiya ◽  
...  
Keyword(s):  
Gold Electrode ◽  
Differential Pulse ◽  
Sample Volume ◽  
Electrochemical Immunosensor ◽  
X Ray ◽  
Sandwich Type ◽  
Pulse Voltammetry ◽  
Culture Filtrate Protein ◽  
Cast Technique ◽  
Screen Printed

A rapid and sensitive sandwich electrochemical immunosensor was developed based on the fabrication of the graphene/polyaniline (GP/PANI) nanocomposite onto screen-printed gold electrode (SPGE) for detection of tuberculosis biomarker 10-kDa culture filtrate protein (CFP10). The prepared GP/PANI nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The chemical bonding and morphology of GP/PANI-modified SPGE were studied by Raman spectroscopy and FESEM coupled with energy dispersive X-ray spectroscopy, respectively. From both studies, it clearly showed that GP/PANI was successfully coated onto SPGE through drop cast technique. Cyclic voltammetry was used to study the electrochemical properties of the modified electrode. The effective surface area for GP/PANI-modified SPGE was enhanced about five times compared with bare SPGE. Differential pulse voltammetry was used to detect the CFP10 antigen. The GP/PANI-modified SPGE that was fortified with sandwich type immunosensor exhibited a wide linear range (20–100 ng/mL) with a low detection limit of 15 ng/mL. This proposed electrochemical immunosensor is sensitive, low sample volume, rapid and disposable, which is suitable for tuberculosis detection in real samples.

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.

Novel HILIC-ESI-MS method for urinary profiling of MSUD and methylmalonic aciduria biomarkers

2019 ◽  
Vol 57 (8) ◽  
pp. 715-723
Author(s):  
Elizabeth Mary Mathew ◽  
Leslie Lewis ◽  
Pragna Rao ◽  
K Nalini ◽  
Asha Kamath ◽  
...  
Keyword(s):  
Formic Acid ◽  
Malonic Acid ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Methylmalonic Aciduria ◽  
Limit Of Quantification ◽  
Maple Syrup ◽  
Effective Manner ◽  
Branched Chain ◽  
Development And Validation

AbstractMethyl malonic acid and branched-chain keto acids are important biomarkers for the diagnosis of cobalamin deficiencies and maple syrup urine disease. We report the development and validation of a HILIC-ESI-MS2 method for the quantification of these organic acids from neonatal urine. The samples were 100 times diluted and analyzed on a ZIC-HILIC column with 25-mM formic acid in water: 25-mM formic acid in acetonitrile (45:55) at a flow rate of 0.8 mL/min with a runtime of only 6 minutes. The method demonstrated a lower limit of detection of 10 ng/mL, Limit of Quantification (LOQ) of 50 ng/mL, linearity of r2 ≥ 0.990 and recoveries of 87–105% for all analytes. The intraday and interday precision CV’s were <10% and 12%, respectively. Extensive stability studies demonstrated the analytes to be stable in stock and in matrix with a percent change within ±15%. The Bland–Altman analysis of the developed method with the gold standard GCMS method demonstrated a bias of 0.44, 0.11, 0.009 and –0.19 for methyl malonic acid, 3-methyl-2-oxovaleric acid, 2-hydroxy-3methylbutyric acid and 4-methyl-2-oxovaleric acid, respectively, proving the methods are comparable. The newly developed method involves no derivatization and has a simple sample preparation and a low runtime, enabling it to be easily automated with a high sample throughput in a cost-effective manner.

scholarly journals Electrochemical Nanocomposite Single-Use Sensor for Dopamine Detection

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3097 ◽  
Author(s):  
Giulia Selvolini ◽  
Cinzia Lazzarini ◽  
Giovanna Marrazza
Keyword(s):  
Limit Of Detection ◽  
Differential Pulse ◽  
Sensor Response ◽  
Sensor Surface ◽  
Serum Samples ◽  
Dopamine Detection ◽  
Sensitive Sensor ◽  
Single Use ◽  
Pulse Voltammetry ◽  
Nanocomposite Sensor

In this work, we report the development of a simple and sensitive sensor based on graphite screen-printed electrodes (GSPEs) modified by a nanocomposite film for dopamine (DA) detection. The sensor was realized by electrodepositing polyaniline (PANI) and gold nanoparticles (AuNPs) onto the graphite working electrode. The sensor surface was fully characterized by means of the cyclic voltammetry (CV) technique using [Fe(CN)6]4−/3− and [Ru(NH3)6]2+/3+ as redox probes. The electrochemical behavior of the nanocomposite sensor towards DA oxidation was assessed by differential pulse voltammetry (DPV) in phosphate buffer saline at physiological pH. The sensor response was found to be linearly related to DA concentration in the range 1–100 μM DA, with a limit of detection of 0.86 μM. The performance of the sensor in terms of reproducibility and selectivity was also studied. Finally, the sensor was successfully applied for a preliminary DA determination in human serum samples.

scholarly journals Development of a Label-Free Electrochemical Aptasensor for the Detection of Tau381 and its Preliminary Application in AD and Non-AD Patients’ Sera

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 84 ◽  
Author(s):  
Dan Tao ◽  
Bingqing Shui ◽  
Yingying Gu ◽  
Jing Cheng ◽  
Weiying Zhang ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Early Stage ◽  
Differential Pulse ◽  
Electrical Signal ◽  
Label Free ◽  
Modified Glassy Carbon Electrode ◽  
Serum Samples ◽  
Pulse Voltammetry ◽  
Aptamer Sensor ◽  
Preliminary Application

The electrochemical aptamer sensor has been designed for detecting tau381, a critical biomarker of Alzheimer′s disease in human serum. The aptasensor is obtained by immobilizing the aptamer on a carboxyl graphene/thionin/gold nanoparticle modified glassy-carbon electrode. As a probe and bridge molecule, thionin connected carboxyl graphene and gold nanoparticles, and gave the electrical signal. Under optimal conditions, the increment of differential pulse voltammetry signal increased linearly with the logarithm of tau381 concentration in the range from 1.0 pM to 100 pM, and limit of detection was 0.70 pM. The aptasensor reliability was evaluated by determining its selectivity, reproducibility, stability, detection limit, and recovery. Performance analysis of the tau381 aptasensor in 10 patients’ serum samples showed that the aptasensor could screen patients with and without Alzheimer′s disease. The proposed aptasensor has potential for use in clinically diagnosing Alzheimer′s disease in the early stage.

scholarly journals Visualization of Aspalathin in Rooibos (Aspalathus linearis) Plant and Herbal Tea Extracts Using Thin-Layer Chromatography

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 938 ◽  
Author(s):  
Emily Amor Stander ◽  
Wesley Williams ◽  
Fanie Rautenbach ◽  
Marilize Le Roes-Hill ◽  
Yamkela Mgwatyu ◽  
...  
Keyword(s):  
Quality Control ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Throughput Screening ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Herbal Tea ◽  
Limit Of Quantification ◽  
Aspalathus Linearis ◽  
Layer Chromatography

Aspalathin, the main polyphenol of rooibos (Aspalathus linearis), is associated with diverse health promoting properties of the tea. During fermentation, aspalathin is oxidized and concentrations are significantly reduced. Standardized methods for quality control of rooibos products do not investigate aspalathin, since current techniques of aspalathin detection require expensive equipment and expertise. Here, we describe a simple and fast thin-layer chromatography (TLC) method that can reproducibly visualize aspalathin in rooibos herbal tea and plant extracts at a limit of detection (LOD) equal to 178.7 ng and a limit of quantification (LOQ) equal to 541.6 ng. Aspalathin is a rare compound, so far only found in A. linearis and its (rare) sister species A. pendula. Therefore, aspalathin could serve as a marker compound for authentication and quality control of rooibos products, and the described TLC method represents a cost-effective approach for high-throughput screening of plant and herbal tea extracts.

Electro-oxidation of captopril at a gold electrode and its determination in pharmaceuticals and human fluids

2015 ◽  
Vol 7 (20) ◽  
pp. 8673-8682 ◽  
Author(s):  
Nagaraj P. Shetti ◽  
Shweta J. Malode ◽  
Sharanappa T. Nandibewoor
Keyword(s):  
Gold Electrode ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Chemical Parameters ◽  
Buffer Solution ◽  
Solution Ph ◽  
Physico Chemical ◽  
Electro Oxidation ◽  
Pulse Voltammetry ◽  
Human Fluids

Gold electrode was used for the oxidation of captopril in phosphate buffer solution pH 3.6 to study the influence of several physico-chemical parameters like potential, scan rate, pH and concentration by cyclic, linear sweep and differential pulse voltammetry.

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