Voltammetric Sensing System for the Detection of Cholesterol Based on the Ni-Bisurea-Pyrographite Composite

2018 ◽  
Vol 769 ◽  
pp. 250-255
Author(s):  
Anastasia A. Lukina ◽  
Daniar V. Ismailov ◽  
Alexander P. Ilyin ◽  
Ksenia V. Derina ◽  
Elena I. Korotkova
Keyword(s):  
Rapid Determination ◽  
Ph Effect ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
High Cholesterol Level ◽  
Modification Procedure ◽  
Voltammetric Sensing ◽  
Electrode Surface Morphology ◽  
Cholesterol Determination

Cholesterol plays a crucial role in the human body. High cholesterol level in blood is a marker of CVDs. Therefore, cholesterol determination techniques are necessary for clinical practice. Currently used cholesterol determination techniques involve enzymes or expensive and complicated equipment. Electrochemical techniques are widely spread in test-systems and sensors construction. Novel modification procedure for enzymeless cholesterol determination is suggested in this study. The electrochemical behavior of cholesterol on modified electrode was studied with the usage of cyclic and differential pulse voltammetry. Obtained concentration range is linear from 0.1 up to 100 mM a conditions close to physiological (pH=6.86) with a quantification limit of 0.01 mM. Besides, the electrode surface morphology and pH-effect were studied. The developed technique is promising for the rapid determination of total cholesterol in blood.

scholarly journals A label-free biosensor based on graphene and reduced graphene oxide dual-layer for electrochemical determination of beta-amyloid biomarkers

2020 ◽  
Vol 187 (5) ◽  
Author(s):  
Jagriti Sethi ◽  
Michiel Van Bulck ◽  
Ahmed Suhail ◽  
Mina Safarzadeh ◽  
Ana Perez-Castillo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Limit Of Detection ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Label Free ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide

AbstractA label-free biosensor is developed for the determination of plasma-based Aβ1–42 biomarker in Alzheimer’s disease (AD). The platform is based on highly conductive dual-layer of graphene and electrochemically reduced graphene oxide (rGO). The modification of dual-layer with 1-pyrenebutyric acid N-hydroxysuccinimide ester (Pyr-NHS) is achieved to facilitate immobilization of H31L21 antibody. The effect of these modifications were studied with morphological, spectral and electrochemical techniques. The response of the biosensor was evaluated using differential pulse voltammetry (DPV). The data was acquired at a working potential of ~ 180 mV and a scan rate of 50 mV s−1. A low limit of detection (LOD) of 2.398 pM is achieved over a wide linear range from 11 pM to 55 nM. The biosensor exhibits excellent specificity over Aβ1–40 and ApoE ε4 interfering species. Thus, it provides a viable tool for electrochemical determination of Aβ1–42. Spiked human and mice plasmas were used for the successful validation of the sensing platform in bio-fluidic samples. The results obtained from mice plasma analysis concurred with the immunohistochemistry (IHC) and magnetic resonance imaging (MRI) data obtained from brain analysis.

scholarly journals Smartphone-based molecularly imprinted sensors for rapid detection of thiamethoxam residues and applications

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258508
Author(s):  
Sihua Peng ◽  
Aqiang Wang ◽  
Yuyang Lian ◽  
Xi Zhang ◽  
Bei Zeng ◽  
...  
Keyword(s):  
Pesticide Residues ◽  
Rapid Detection ◽  
Rapid Determination ◽  
Detection System ◽  
Residue Analysis ◽  
Differential Pulse ◽  
Detection Technology ◽  
Screen Printed Carbon Electrode ◽  
Relative Standard

In order to achieve rapid detection of thiamethoxam residues in mango, cowpea and water, this study modified the screen printed carbon electrode (SPCE) to make a specific molecular imprinting sensor (Thiamethoxam-MIP/Au/rGO/SPCE) for thiamethoxam. An integrated smartphone platform was also built for thiamethoxam residue analysis. The performance of the complete system was analyzed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The system was then applied for the rapid determination of thiamethoxam residues in water, mango and cowpea samples. The results showed that the molecular sensor showed good linearity in the range 0.5–3.0 μmol/L of thiamethoxam. The detection limit of thiamethoxam was 0.5 μmol/L. Moreover, the sensor had good reproducibility and anti-interference performance. The average recovery rates of the pesticide residues in water, mango and cowpea samples were in the range of 90–110% with relative standard deviations < 5%. The rapid detection system for thiamethoxam residue constructed in this study was simple, reliable, reproducible and had strong anti-interference. It has broad application prospects in the field detection of thiamethoxam residue, and serves as a valuable reference for the further development of rapid detection technology of pesticide residues in the field of environment and food safety.

scholarly journals Fabrication of novel polymer-modified graphene-based electrochemical sensor for the determination of mercury and lead ions in water and biological samples

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chenthattil Raril ◽  
Jamballi G. Manjunatha
Keyword(s):  
Heavy Metal ◽  
Detection Limit ◽  
Metal Ions ◽  
Biological Samples ◽  
Heavy Metal Ions ◽  
Electrochemical Techniques ◽  
Differential Pulse ◽  
Modified Graphene ◽  
Water And Biological Samples

Abstract Background This paper presents the application of polyglycine-modified graphene paste electrode (PGMGPE) for the electrochemical detection of Hg (II) and Pb (II) ions in the water and biological samples. Method The developed electrode was characterized by field emission scanning electron microscopy. Electrochemical techniques such as cyclic voltammetry and differential pulse voltammetry were used to study the behavior of metal ions. Results The modification process improves the electrochemical behavior of heavy metal ions. The peak current varied linearly with the increase of the concentration leading to a detection limit of 6.6 μM (Hg (II)) and 0.8 μM (Pb (II)), respectively. Conclusion The developed electrode exhibits good sensitivity, selectivity, stability, and lower detection limit, and was successfully applied to the determination of heavy metal ions in water and biological samples with a good recovery range.

Rapid Determination of Cholesterol in Single and Multicomponent Prepared Foods

1993 ◽  
Vol 76 (4) ◽  
pp. 902-906 ◽  
Author(s):  
Sami M Al-Hasani ◽  
Jan Hlavac ◽  
Mark W Carpenter
Keyword(s):  
Rapid Method ◽  
Coefficient Of Variation ◽  
Rapid Determination ◽  
Collaborative Study ◽  
Gas Chromatograph ◽  
Vegetable Soup ◽  
Aoac Method ◽  
Solvent Use ◽  
Cholesterol Determination

Abstract A rapid method has been developed for cholesterol determination in single and multicomponent foods. The method involves alcoholic KOH saponification of the samples, extraction of the nonsaponif iable fraction with hexane, and injection of concentrated extract into the gas chromatograph without derivatizations. It has been applied to a wide variety of frozen and refrigerated foods. More than 300 samples were analyzed with a coefficient of variation (CV) ranging from 0.5 to 8.6%. The average recoveries of cholesterol from spiked oil and tomato vegetable soup samples were 100 ±1.5% and 99.7 ±1.6% and the CVs were 1.5 and 1.6%, respectively. This method reduces labor by &gt;70%, eliminates dangerous chemicals, and minimizes solvent use, compared to the AOAC method and other methods cited in the manuscript. The method was used successfully on a wide variety of multicomponent foods. We recommend this method for collaborative study under the AOAC guidelines for method approval.

scholarly journals Square wave and differential pulse voltammetric methods for the analysis of olivetol at gold electrode

2017 ◽  
Vol 7 (2) ◽  
pp. 77
Author(s):  
Jyoti T. Bagalkoti ◽  
Vijay P. Pattar ◽  
Sharanappa T. Nandibewoor
Keyword(s):  
Gold Electrode ◽  
Supporting Electrolyte ◽  
Electrochemical Techniques ◽  
Antitumor Agent ◽  
Differential Pulse ◽  
Oxidation Peak ◽  
Square Wave ◽  
Effects Of Ph ◽  
Plausible Mechanism

<p class="PaperAbstract"><span lang="EN-US">Few electrochemical techniques have been employed for the determination of the powerful antitumor agent olivetol (OLV) in real samples at gold electrode. An intense and well pronounced oxidation peak was obtained at 1.04 V in the phosphate buffer pH 5.0 as the supporting electrolyte. The effects of pH and scan rate on the oxidation peak were studied. The electrochemical behavior of OLV was investigated using cyclic voltammetric (CV), square wave voltammetric (SWV) and differential pulse voltammetric (DPV) techniques. In DPV and SWV, the gold electrode showed a good sensitivity for OLV in a linear range of 0.1-1.5 µM and 0.1-1.3 µM and detection limits of 1.936×10<sup>-9</sup> M and 4.754</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-9</sup> M, respectively. A plausible mechanism involving an adsorption controlled oxidation reaction was deduced. The effect of various excipients was also studied and the method was successfully applied for the determination of OLV in human biological samples. </span></p>

Voltammetric determination of Nordiazepam at meniscus modified silver solid amalgam electrode

2014 ◽  
Vol 7 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Petr Samiec ◽  
Zuzana Navrátilová
Keyword(s):  
Ph Value ◽  
Ph Effect ◽  
Differential Pulse ◽  
Current Response ◽  
Limit Of Quantification ◽  
Silver Solid Amalgam Electrode ◽  
Amalgam Electrode ◽  
Optimum Ph ◽  
Pulse Voltammetry

Abstract New electrochemical method for determination of Nordiazepam (NDZ) at meniscus modified silver solid amalgam electrode (m-AgSAE) was developed utilizing differential pulse voltammetry (DPV). The pH effect on the current response of NDZ was studied in the mixture of Britton-Robinson buffer (BR) and methanol (9:1) with optimum pH value of 10. The calibration dependences were examined under the optimal conditions and linearity in the range from 2 × 10−6 to 1 × 10−4 mol L−1 with limit of quantification of 1.7 × 10−6 mol L−1 were accomplished.

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