scholarly journals Bio-Active Free Direct Optical Sensing of Aflatoxin B1 and Ochratoxin A Using a Manganese Oxide Nano-System

2021 ◽  
Vol 2 ◽  
Author(s):  
Avinash Kumar Singh ◽  
G. B. V. S. Lakshmi ◽  
Tarun Kumar Dhiman ◽  
Ajeet Kaushik ◽  
Pratima R. Solanki
Keyword(s):  
Manganese Oxide ◽  
Ochratoxin A ◽  
Food Quality ◽  
Limit Of Detection ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Maximum Absorbance ◽  
Point Of Use ◽  
Fixed Concentration ◽  
Co Precipitation

Aflatoxins-B1 (AFB1) and Ochratoxin-A (OchA) are the two types of major mycotoxin produced by Aspergillus flavus, Aspergillus parasiticus fungi, Aspergillus carbonarius, Aspergillus niger, and Penicillium verrocusumv. These toxins are mainly found in metabolite cereals, corn, coffee beans, and other oil-containing food items. Excessive consumption of these toxins can be carcinogenic and lead to cancer. Thus, their rapid testing became essential for food quality control. Herein, manganese oxide nanoparticles (MnO2 nps) have been proposed to explore the interaction with AFB1 and OchA using UV-visible spectroscopy. MnO2 nps were synthesized using the co-precipitation method. They were pure and crystalline with an average crystallite size of 5–6 nm. In the UV-vis study, the maximum absorbance for MnO2 nps was observed around 260 nm. The maximum absorbance for AFB1 and OchA was observed at 365 and 380 nm, respectively, and its intensity enhanced with the addition of MnO2 nps. Sequential changes were observed with varying the concentration of AFB1 and OchA with a fixed concentration of MnO2 nps, resulting in proper interaction. The binding constant (kb) and Gibbs free energy for MnO2 nps-AFB1 and OchA were observed as 1.62 × 104 L g−1 and 2.67 × 104 L g−1, and −24.002 and −25.256 kJ/mol, respectively. The limit of detection for AFB1 and OchA was measured as 4.08 and 10.84 ng/ml, respectively. This bio‐active free direct sensing approach of AFB1 and OchA sensing can be promoted as a potential analytical tool to estimate food quality rapidly and affordable manner at the point of use.

XRD and Photoluminescence Properties of CaSO4:Dy Phosphor Synthesized by New Co-Precipitation Method

2017 ◽  
Vol 888 ◽  
pp. 333-337 ◽  
Author(s):  
Nadira Kamarudin ◽  
Wan Saffiey Wan Abdullah ◽  
Muhammad Azmi Abdul Hamid
Keyword(s):  
Calcium Sulfate ◽  
Average Crystallite Size ◽  
Information Storage ◽  
Precipitation Method ◽  
Photoluminescence Properties ◽  
Orthorhombic Crystal ◽  
Phosphor Material ◽  
X Ray ◽  
Wide Range ◽  
Co Precipitation

This paper presents the luminescence properties of dysprosium (Dy) doped calcium sulfate (CaSO4) phosphor material produced by co-precipitation technique with 0.1 - 0.5 mol% concentration of dopant. The crystallinity of the produced powder was studied using x-ray powder diffraction (XRD). The XRD spectrum shows high purity anhydrite CaSO4 phosphor material produced. The average crystallite size of 74 nm with orthorhombic crystal system was obtained. The luminescence behavior of produced CaSO4: Dy was studied using a photoluminescence (PL) spectrometer. The excitation and emission spectrum peaks associated with defects and vacancies of the phosphor material at claimed crystalline phase. The mixed peaks of excitation and emission that corresponds to micro and nano sized particle was shown for the produced powders. These properties show that the produced powders have wide range of luminescence detection with many electron traps ready for thermoluminescence (TL) information storage.

scholarly journals Synthesis of BaTi5O11 by an aqueous co-precipitation method via stable organic titanate precursor

2021 ◽  
pp. 14-14
Author(s):  
Pelin Aktaş
Keyword(s):  
Aqueous Media ◽  
Average Crystallite Size ◽  
Phase Evolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Ft Ir ◽  
Scherrer Formula ◽  
Co Precipitation

BaTi5O11 has been widely researched due to its unique microwave properties. Conventionally it is challenging to obtain this compound as a single phase. The BaTi5O11 was synthesized via co-precipitation technique using an aqueous solution of titanium(IV)(triethanolaminato) isopropoxide, barium nitrate and ammonia as precursors which are stable in an aqueous media. The phase evolution, purity, and structure were identified by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy analysis. The desired BaTi5O11 structure was obtained by calcination at 900?C. Furthermore, the structure is characterized by TGA, FT-IR and Raman studies. The study showed that the particles were between 80 and 120 nm in size and the average crystallite size was determined from the Scherrer formula as 68.1 nm at 900?C.

Characterization and Stability Monitoring of Maghemite Nanoparticle Suspensions

2012 ◽  
Vol 576 ◽  
pp. 398-401 ◽  
Author(s):  
Irwan Nurdin ◽  
Idris Yaacob Iskandar ◽  
M. Rafie Johan ◽  
Bee Chin Ang
Keyword(s):  
Zeta Potential ◽  
Magnetic Measurement ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Hydrodynamic Diameter ◽  
Maghemite Nanoparticles ◽  
Nanoparticle Suspensions ◽  
Maghemite Nanoparticle ◽  
The Stability ◽  
Co Precipitation

Maghemite nanoparticle suspensions were synthesized using a co-precipitation method and characterized by a variety of techniques including XRD, TEM, magnetic measurement, DLS, and zeta potential. The stability of the suspension was monitored by measuring the particle size distribution using DLS over a period of two months. The diffraction pattern from XRD measurement confirmed that the particles were maghemite with an average crystallite size of 9.4 nm. TEM observations and analyses showed that the geometry of maghemite nanoparticles were nearly spherical with a mean physical diameter of 9.9 nm. The maghemite nanoparticles showed superparamagnetic behavior with saturation magnetization value of 32.20 emu/g. The mean hydrodynamic diameter of the suspension remained unchanged after two months which indicated no formation of aggregation. The hydrodynamic diameters recorded were 45.1 nm and 48.4 nm, respectively. Additionally, lack of sedimentation indicated that the suspension was stable. The suspension’s zeta potential values were 41.5 mV and 40.4 mV for as synthesized and after two month of storage respectively.

scholarly journals Synthesis and Characterization of Pure and Rare-Earth Metal Gd Doped SnO2-CuO Nanoparticles by Co-Precipitation Method

2018 ◽  
Vol 4 (5) ◽  
pp. 478-482
Author(s):  
L. Prakash ◽  
C. Tirupathi
Keyword(s):  
Rare Earth ◽  
Band Gap ◽  
Crystallite Size ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Average Crystallite Size ◽  
Cuo Nanoparticles ◽  
Precipitation Method ◽  
Pure Sno2 ◽  
Co Precipitation

Pure and rare-earth metal Gd doped SnO2-CuO nanoparticles were successfully prepared from the starting materials SnCl2, CuCl2 and doping element gadolinium nitrate. Pure and Gd doped SnO2-CuO were synthesized by co-precipitation method. The samples were characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), UV-Vis, SEM, EDX and dielectric studies. The XRD analysis reveals that the rare-earth metal Gd dopants were substituted into rutile SnO2-CuO nanoparticles. Pure SnO2-CuO nanoparticles have an average crystallite size of 15 nm and rare-earth metal Gd doped SnO2-CuO nanoparticles have 18 nm. The average crystallite size of the sample increases when dopant was used and XRD peak intensity also increases when compared to pure SnO2-CuO nanoparticles. The optical absorption measurements exposed the nanometric size of the materials influences the energy band gap. Optical band gap was found to be 5.08 eV for pure SnO2-CuO nanoparticles and 5.14 eV for Gd doped SnO2-CuO nanoparticles. Surface morphology of pure and Gd doped SnO2-CuO nanoparticles annealed at 400 °C shows that most of the particles are rod shaped and hence it may have better sensitivity. Dielectric constant and dielectric loss decrease with increasing frequency at 100 °C and 200 °C. Doped samples show larger dielectric properties than pure SnO2-CuO nanoparticles.

scholarly journals Effect of Ni doping on structural, optical and photocatalytic properties of Zn1-XNiXO nanoparticles prepared by different pH conditions

2013 ◽  
Vol 12 (6) ◽  
pp. 4097-4107 ◽  
Author(s):  
R. Jeyachitr ◽  
N. Sriharan ◽  
V. Senthilnathan ◽  
T. S. Senthil
Keyword(s):  
Average Crystallite Size ◽  
Hexagonal Wurtzite Structure ◽  
Photocatalytic Properties ◽  
Precipitation Method ◽  
Ni Doping ◽  
Zno Nanocrystals ◽  
Structure Morphology ◽  
Ph Conditions ◽  
Doped Zno ◽  
Co Precipitation

Zn1-XNiXO (x = 0.00, 0.02, 0.04 & 0.06 mol %) nanoparticles were prepared by simple co-precipitation method. The influences of Ni doping on structure, morphology, optical and photocatalytic properties were investigated by means of Xray diffraction, scanning electron microscopy, UV–Vis spectrophotometer and photochemical reaction method. The obtained result shows that the prepared ZnO nanocrystals were hexagonal wurtzite structure and the average crystallite size decreases with increase of Ni doping. The increase of visible light absorption and increase of band gap were found with the increase of Ni doping concentration, which enable the sample harvest more photons to excite the electron from valence band. The photocatalytic properties of Ni doped ZnO nanocrystals shows enhanced activity that the pure ZnO nanocrystals. The photocatalytic activities were not significantly affected by the particle size and 0.04% Ni doped ZnO nanocrystals shows best catalytic activity than the other catalysts.

scholarly journals Ga2O3(Sn) Oxides for High-Temperature Gas Sensors

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2938
Author(s):  
Nataliya Vorobyeva ◽  
Marina Rumyantseva ◽  
Vadim Platonov ◽  
Darya Filatova ◽  
Artem Chizhov ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Sensors ◽  
Photoelectron Spectroscopy ◽  
Average Crystallite Size ◽  
Nitrogen Adsorption ◽  
Precipitation Method ◽  
X Ray ◽  
Adsorption Sites ◽  
Co Precipitation ◽  
High Temperature Gas

Gallium(III) oxide is a promising functional wide-gap semiconductor for high temperature gas sensors of the resistive type. Doping of Ga2O3 with tin improves material conductivity and leads to the complicated influence on phase content, microstructure, adsorption sites, donor centers and, as a result, gas sensor properties. In this work, Ga2O3 and Ga2O3(Sn) samples with tin content of 0–13 at.% prepared by aqueous co-precipitation method were investigated by X-ray diffraction, nitrogen adsorption isotherms, X-ray photoelectron spectroscopy, infrared spectroscopy and probe molecule techniques. The introduction of tin leads to a decrease in the average crystallite size, increase in the temperature of β-Ga2O3 formation. The sensor responses of all Ga2O3(Sn) samples to CO and NH3 have non-monotonous character depending on Sn content due to the following factors: the formation of donor centers and the change of free electron concentration, increase in reactive chemisorbed oxygen ions concentration, formation of metastable Ga2O3 phases and segregation of SnO2 on the surface of Ga2O3(Sn) grains.

A correlated structural and electrical study of manganese ferrite nanoparticles with variation in sintering temperature

2017 ◽  
Vol 31 (26) ◽  
pp. 1750236 ◽  
Author(s):  
Elangbam Chitra Devi ◽  
Ibetombi Soibam
Keyword(s):  
Structural Changes ◽  
Spinel Phase ◽  
Spinel Ferrite ◽  
Average Crystallite Size ◽  
Ferrite Nanoparticles ◽  
Precipitation Method ◽  
Manganese Ferrite ◽  
Absorption Bands ◽  
Metal Chlorides ◽  
Co Precipitation

Manganese ferrite nanoparticles were prepared by chemical co-precipitation method. Metal chlorides and sodium hydroxide were used as precursor. The spinel phase formation of the prepared samples was confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). From the XRD data, the average crystallite size and lattice constant were calculated. FTIR spectra reveal the characteristic absorption bands of spinel ferrite due to M-O stretching vibrations in tetrahedral and octahedral sites. Manganese ferrite nanoparticles were further given sintering. The effect of sintering at different temperatures on the structural properties such as XRD, FTIR and electrical properties such as dielectric constant, dielectric loss and ac-conductivity was studied. Possible mechanism of structural changes and observed electrical behavior due to sintering is being discussed. A strong correlation has also been observed in the results obtained from different characterization techniques.

Green Chemistry Preparation of thiochromeno[4,3-b]pyran and benzo[h]thiazolo[2,3-b]quinazoline Derivatives using HSBM Technique over ZnAl2O4 Nano-Powders

2019 ◽  
Vol 22 (6) ◽  
pp. 421-427
Author(s):  
Seyyed Jalal Roudbaraki ◽  
Sadaf Janghorban ◽  
Majid Ghashang
Keyword(s):  
High Speed ◽  
Average Particle Size ◽  
Reaction Times ◽  
Environmentally Friendly ◽  
Average Crystallite Size ◽  
Precipitation Method ◽  
Average Particle ◽  
Efficient Catalyst ◽  
Quinazoline Derivatives ◽  
Co Precipitation

Aim and Objective: The aim of this paper is to introduce HSBM as a green and environmentally friendly technique for the synthesis of thiochromeno[4,3-b]pyran and benzo[h]thiazolo[2,3-b]quinazoline derivatives over ZnAl2O4 nanopowders as an efficient catalyst. Materials and Methods: ZnAl2O4 nanopowders were synthesized via a co-precipitation of Zn(NO3)2 and Al(NO3)3 salts and were characterized by XRD, FE-SEM, TEM and DLS techniques. The as-prepared ZnAl2O4 nano-powders have been used as a catalyst on the synthesis of pyran nucleus using high-speed ball milling (HSBM) technique. The structure of products was confirmed with NMR analysis. Results: ZnAl2O4 exhibits a cubic crystal structure (Space group: Fd-3m) with the average crystallite size of 41 nm. The average particle size of ZnAl2O4 nano-powders determined by DLS technique is 55 nm. The catalytic activity of nano-powders was examined on the synthesis of 2- amino-4,5-dihydro-4-arylthiochromeno[4,3-b]pyran-3-carbonitriles, (8Z)-2-amino-8-arylidene-4,5, 7,8-tetrahydro-4-arylthiopyrano[4,3-b]pyran-3-carbonitriles, 4-aryl-3,4,5,6-tetrahydrobenzo[h]quinazoline- 2(1H)-thiones and 4-aryl-1,3,4,5-tetrahydro-2H-thiochromeno[4,3-d]pyrimidine-2-thione derivatives. All products were obtained in high yields with short reaction times. Conclusion: ZnAl2O4 nanopowders were prepared via a cost-effective co-precipitation method and showed good potential for the synthesis of 4H-pyran analogous in good yields. The salient advantages of HSBM technique include environmentally friendly with reduced solvents, is a simple technique and has low energy costs.

Synthesis, Characterization and Photocatalytic Activities of Bismuth Vanadate by Facile Co-Precipitation Method

2010 ◽  
Vol 148-149 ◽  
pp. 1469-1472
Author(s):  
Chao Jun Liu ◽  
Yue Hua Xu
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Average Crystallite Size ◽  
Temperature Treatment ◽  
Precipitation Method ◽  
High Temperature Treatment ◽  
Synthesis Conditions ◽  
High Efficient ◽  
Photocatalytic Activities ◽  
Co Precipitation ◽  
Monoclinic Bivo4

Monoclinic BiVO4 photocatalysts were synthesized via facile and straightforward co-precipitation method at room temperature without high temperature treatment and characterized with X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), flourier transfer infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), and transmission electron microscopy (TEM). The results indicate that through proper selection of synthesis conditions, it is possible to obtain high efficient BiVO4 nanoparticles. The as-prepared monoclinic BiVO4 photocatalysts have an average crystallite size of about 20 nm with the particle size of about 20 to 50 nm. Their photocatalytic activities were evaluated by decolorization of rhodamine B in aqueous solution under visible light irradiation, and the relationship between the photocatalytic activity of BiVO4 and their physicochemical properties were investigated.

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