scholarly journals Interactive Studies on Synthetic Nanopolymer decorated with Edible Biopolymer and its Selective Electrochemical determination of L-Tyrosine

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nathiya Dhananjayan ◽  
Wilson Jeyaraj ◽  
Gurunathan Karuppasamy
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Electrochemical Determination ◽  
Electrochemical Analysis ◽  
Oxidation Potential ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Selective Determination ◽  
Adhesive Surface ◽  
Effective Role

Abstract Herein, an edible biopolymer amine Modified Gum Acacia (MGA), successfully encumbered with Electron Beam irradiated Polypyrrole Nanospheres (EB-PPy NSs), was investigated for the effective role in L-Tyrosine (Tyr) biosensing application. The morphology of EB-PPy NSs decorated MGA (EB-PPy/MGA) hybrid nanobiocomposite has been studied by Scanning electron microscopy and its affirmed interactions were characterized by X-ray diffraction, Raman, FT-IR spectroscopy, UV-Visible spectroscopy, Thermo Gravimetric Analysis and Vibrating Sample Magnetometer. The hybrid nanobiocomposite manifested diamagnetic behavior with reduced saturation magnetization (Ms = 1.412 × 10−4 emu/g) to produce more adhesive surface. Amine chains in EB-PPy NSs and hydroxyl groups of MGA contributed to effective immobilization, thus enabling suitable orientation for Tyr determination. The electrochemical analysis illustrated that the proposed nanobiocomposite based sensor exhibited an excellent electrocatalytic activity toward selective determination of Tyr in the linear range of 0.4 to 600 µM with a lower detection limit of 85 nM, low oxidation potential of 0.72 V and good selectivity. Finally, the reliability of the constructed EB-PPy/MGA for Tyr detection was demonstrated in real samples.

The Effect of External Conditions on Ignition Temperature of Thermoplastic Polyurethane Elastomers

2013 ◽  
Vol 838-841 ◽  
pp. 14-17
Author(s):  
Ivana Turekova ◽  
Zuzana Szabova ◽  
Tomas Chrebet ◽  
Jozef Harangozo
Keyword(s):  
Thermal Degradation ◽  
Ignition Temperature ◽  
Thermoplastic Polyurethane ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Polyurethane Elastomers ◽  
External Conditions ◽  
Thermoplastic Polyurethane Elastomers ◽  
The Impact

The paper reports a study of the impact of moisture and age of pellets, as well as an external condition, on the thermal degradation of the thermoplastic polyurethane elastomers. Because thermoplastic polyurethane elastomers are hydroscopic polymer, moisture will have a significant impact on thermal degradation. For determination of the effect of moisture and age were used the thermo gravimetric analysis, differential scanning calorimeter and ISO STN 871: Plastics. Determination of ignition temperature using a hot-air furnace.

Physical and Thermal Properties of Chitosan

2014 ◽  
Vol 979 ◽  
pp. 315-318 ◽  
Author(s):  
W. Siriprom ◽  
K. Chantarasunthon ◽  
K. Teanchai
Keyword(s):  
Physical Properties ◽  
Thermo Gravimetric Analysis ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Biodegradable Films ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Good Agreement

This work aims at characterizing the thermal and physical properties of chitosan. The samples were evaluated for potentiality to use as raw material for biodegradable films raw material. Their thermal and physical properties have been also discussed in detail which Fourier Transform Infrared Spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA), Energy Dispersive X-Ray Fluorescence (EDXRF) and X-Ray Diffraction (XRD), respectively. The result of the XRD pattern indicated the sample has amorphous-crystalline structure and FTIR results confirmed the formation of intermolecular hydrogen bonding between the amino and hydroxyl groups of the sample. In good agreement between the EDXRF and TGA results, noticed that the removal of moisture and volatile material.

scholarly journals Determination of capsaicin using carbon nanotube based electrochemical biosensors

2016 ◽  
Author(s):  
◽  
Thabani Eugene Mpanza
Keyword(s):  
Electron Transfer ◽  
Thermo Gravimetric Analysis ◽  
Computational Techniques ◽  
Gravimetric Analysis ◽  
Multiwalled Carbon ◽  
Chilli Pepper ◽  
Redox Mechanism ◽  
Docking Simulations ◽  
Analytical Technique

This study involves the development of a sensitive electrochemical biosensor for the determination of capsaicin extracted from chilli pepper fruit, based on a novel signal amplification strategy. The study therefore, seeks to provide a sensitive electro-analytical technique to be used for the determination of capsaicin in food and spicy products. Electrochemical measurements using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) modes were utilized in order to understand the redox mechanism of capsaicin and to test the performance of the developed biosensor supported with computational techniques. In this work two different enzymes, Phenylalanine ammonia lyase (PAL) and Glucose oxidase (GOx) were used for electrode modifications respectively. For this purpose three different types of working electrodes namely: glassy carbon electrode (GCE), platinum electrode (Pt-E) and gold electrode (Au-E) were used and their performances were compared. For the first time, the three electrodes were modified with PAL and GOx enzymes on multiwalled carbon nanotubes used in this study and characterized by attenuated total reflectance infrared spectroscopy, transmittance electron microscopy and thermo-gravimetric analysis supported by computational methods. The comparison of the results obtained from the bare and modified platinum electrodes revealed the sensitivity of the developed biosensor with modified electrode having high sensitivity of 0.1863 µg.L-1 and electron transfer rate constant (ks) of 3.02 s-1. To understand the redox mechanism completely, adsorption and ligand-enzyme docking simulations were carried out. Docking studies revealed that capsaicin formed hydrogen bonds with Glutamates (GLU355, GLU541, GLU586), Arginine (ARG) and other amino acids of the hydrophobic channel of the binding sites which facilitated the redox reaction for detection of capsaicin. These results confirm that the PAL enzyme facilitated the electron transfer from the capsaicin ligand, hence improving the biosensing response. Our results suggest potential applications of this methodology for the determination of capsaicin in the food industry.

scholarly journals Cerium(IV) and Iron(III) Oxides Nanoparticles Based Voltammetric Sensor for the Sensitive and Selective Determination of Lipoic Acid

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7639
Author(s):  
Guzel Ziyatdinova ◽  
Liliya Gimadutdinova
Keyword(s):  
Lipoic Acid ◽  
Inorganic Ions ◽  
Fold Increase ◽  
Living Organism ◽  
Oxidation Potential ◽  
Acid Oxidation ◽  
Voltammetric Sensor ◽  
Pharmaceutical Dosage Forms ◽  
Selective Determination

A novel voltammetric sensor based on СеO2·Fe2O3 nanoparticles (NPs) has been developed for the determination of lipoic acid, playing an essential role in aerobic metabolism in the living organism. Sensor surface modification provides a 5.6-fold increase of the lipoic acid oxidation currents and a 20 mV anodic shift of the oxidation potential. The best voltammetric parameters have been obtained for the 0.5 mg mL−1 dispersion of СеO2·Fe2O3 NPs. Scanning electron microscopy (SEM) confirms the presence of spherical NPs of 25–60 nm, and their aggregates evenly distributed on the electrode surface and formed porous coverage. This leads to the 4.4-fold increase of the effective surface area vs. bare glassy carbon electrode (GCE). The sensor shows a significantly higher electron transfer rate. Electrooxidation of lipoic acid on СеO2·Fe2O3 NPs modified GCE is an irreversible diffusion-controlled pH-independent process occurring with the participation of two electrons. The sensor gives a linear response to lipoic acid in the ranges of 0.075–7.5 and 7.5–100 μM with the detection limit of 0.053 μM. The sensor is selective towards lipoic acid in the presence of inorganic ions, ascorbic acid, saccharides, and other S-containing compounds. The sensor developed has been tested on the pharmaceutical dosage forms of lipoic acid.

scholarly journals Promoting Effect of Inorganic Alkali on Carbon Dioxide Adsorption in Amine-Modified MCM-41

2016 ◽  
Author(s):  
Yang Teng ◽  
Lijiao Li ◽  
Gang Xu ◽  
Kai Zhang ◽  
Kaixi Li
Keyword(s):  
Co2 Adsorption ◽  
Thermo Gravimetric Analysis ◽  
Critical Factor ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Carbon Dioxide Adsorption ◽  
Dependence Relation ◽  
Promoting Effect ◽  
Ft Ir ◽  
Mcm 41

Three kinds of inorganic alkali are introduced into tetraethylenepentamine (TPEA) and polyethyleneimine (PEI) modified MCM-41 as the CO2 adsorbents. FT-IR and TGA are used to characterize the surface groups and the thermal stability of adsorbents. Chemical titration method is used to measure the alkali amounts of adsorbents. Thermo-gravimetric analysis with 10%CO2/N2 as the simulated flue gas is used to test the CO2 adsorption performance of adsorbents. The results show that all three kinds of inorganic alkali containing adsorbents exhibit promoted CO2 adsorption capability than traditional TPEA and PEI modified samples. Ca(OH)2 and PEI modified samples exhibit the highest adsorption capacity and stable regeneration property. The introduction of inorganic alkali changes the chemical adsorption mechanism between CO2 and increases the effective alkali amounts due to its hydroxyl groups. The CO2 adsorption capacities have a linear dependence relation with the alkali amounts of adsorbents, indicating that alkali amount is a critical factor for novel adsorbents exploring.

scholarly journals Surface modification of nano-TiN by using silane coupling agent

2014 ◽  
Vol 32 (2) ◽  
pp. 214-219 ◽  
Author(s):  
Guojun Cheng ◽  
Jiaqi Luo ◽  
Jiasheng Qian ◽  
Jibin Miao
Keyword(s):  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Thermo Gravimetric Analysis ◽  
Nano Particles ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Transmission Electron Micrograph ◽  
Covalent Bonds ◽  
Blending Method ◽  
Silane Coupling

AbstractTitanium nitride (TiN) nano-particles were subjected to graft modification by silane coupling agent (KH-570) via a direct blending method. The hydroxyl groups on the surface of TiN nano-particles can interact with silanol groups [-Si-OCH3] of KH-570 forming an organic coating layer. The covalent bonds (Ti-O-Si) formation was testified by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS). Through transmission electron micrograph (TEM) observations, it was found that KH-570 could improve the dispersibility of nano-TiN particles in ethyl acetate. Thermo gravimetric analysis (TGA) and contact angle measurements indicated that KH-570 molecules were adsorbed or anchored on the surface of nano-TiN particle and the net efficiency of it was 22.76 %, which facilitated to hinder the aggregation of nano-TiN particles.

Synthesis and Evaluation Methacrylate-Based Monolithic Materials Mixed with Carbon Nanotubes

2014 ◽  
Vol 900 ◽  
pp. 378-381
Author(s):  
Rui Feng
Keyword(s):  
Mercury Intrusion Porosimetry ◽  
Thermo Gravimetric Analysis ◽  
Reversed Phase ◽  
Gravimetric Analysis ◽  
Reversed Phase Liquid Chromatography ◽  
Hydrophobic Properties ◽  
Thermo Gravimetric ◽  
Mercury Intrusion ◽  
Phase Liquid

An effective approach to synthesize methacrylate-based hybrid monoliths was carried out by photopolymerization and the properties of the obtained monoliths mixed with mult-wall carbon nanotube (MWNT) were studied in this paper. The prepared hybrid materials with MWNT in the range of 0-5% total weight of monomers were characterized by Fourier transform infrared spectra, thermo-gravimetric analysis (TGA), and mercury intrusion porosimetry, respectively. Moreover, their porosities were evaluated by the determination of flow rate for different prepared monolithic capillaries. The results showed that the monoliths with more MWNT (1-5%) possessed larger pore sizes between 1-10 μm. The hybrid monoliths have the potential advantages including stronger hydrophobic properties and less resistance for the application of reversed phase liquid chromatography in the micro-column separation.

Characterisation of Hydroxyapatite/Bacterial Cellulose Nanocomposites

2009 ◽  
Vol 17 (6) ◽  
pp. 353-358 ◽  
Author(s):  
Shengnan Zhang ◽  
Guangyao Xiong ◽  
Fang He ◽  
Yuan Huang ◽  
Yulin Wang ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Bacterial Cellulose ◽  
Photoelectron Spectroscopy ◽  
Thermo Gravimetric Analysis ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Cellulose Nanocomposites

A novel nanocomposite material consisting of hydroxyapatite (HAp) deposited on a phosphorylated bacterial cellulose (BC) has been synthesised via a biomimetic route. X-ray photoelectron spectroscopy (XPS) showed that phosphate groups were successfully introduced to the hydroxyl groups of BC by phosphorylation reaction to promote the growth of calcium phosphate. Transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) patterns of HAp/BC demonstrated that HAp crystals wrap the surfaces of BC fibres. In this work, HAp/BC nanocomposites were studied using thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA result suggested that HAp/BC nanocomposite, similar to natural bone in terms of composition, contained carbonate ions, in agreement with our previous Fourier transform infrared (FTIR) spectroscopy results. Thermal behaviour differences between BC and HAp/BC were observed by differential scanning calorimetry (DSC). The thermal stability of HAp/BC obtained from DSC showed an improvement when compared to that of a pure BC sample.

Determination of Composition of Cellulose and Lignin Mixtures Using Thermo Gravimetric Analysis (TGA)

2007 ◽  
Author(s):  
Kaushlendra Singh ◽  
Mark Risse ◽  
K. C. Das ◽  
John Worley
Keyword(s):  
Lignin Content ◽  
Preliminary Investigation ◽  
Linear Equations ◽  
Thermo Gravimetric Analysis ◽  
Rate Of Change ◽  
Unit Weight ◽  
Gravimetric Analysis ◽  
Thermo Gravimetric ◽  
Bio Oil

The proportional composition of cellulose, hemicellulose, lignin and minerals in a biomass plays a significant role in the proportion of pyrolysis products (bio-oil, char, and gases). Traditionally, the composition of biomass is chemically determined, which is a time consuming process. This paper presents the results of a preliminary investigation of a method using thermo-gravimetric analysis for predicting the fraction of cellulose and lignin in lignin-cellulose mixtures. The concept is based on a newly developed theory of Pyrolytic Unit Thermographs (PUT). The Pyrolytic Unit Thermograph (PUT) is a thermograph showing rate of change of biomass weight with respect to temperature for a unit weight loss. These PUTs were used as input for two predictive mathematical procedures that minimize noise to predict the fractional composition in unknown lignin-cellulose mixtures. The first model used linear correlations between cellulose/lignin content and peak decomposition rate while the second method used a system of linear equations. Results showed that both models predicted the composition of lignin-cellulose mixture within 7 to 18% of measured value. The promising results of this preliminary study will certainly motivate further refinement of this method through advanced research.

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