scholarly journals Simultaneous Analysis of Hydroquinone, Arbutin, and Ascorbyl Glucoside Using a Nanocomposite of Ag@AgCl Nanoparticles, Ag2S Nanoparticles, Multiwall Carbon Nanotubes, and Chitosan

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1583
Author(s):  
Nutthaya Butwong ◽  
Thidarat Kunawong ◽  
John H. T. Luong
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
High Performance ◽  
Multiwall Carbon Nanotubes ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Simultaneous Analysis ◽  
Measured Concentration ◽  
Multi Walled Carbon Nanotubes ◽  
Ag2s Nanoparticles

A nanocomposite comprising Ag nanoparticles on AgCl/Ag2S nanoparticles was decorated on multi-walled carbon nanotubes and used to modify a glassy carbon electrode. Chitosan was also formulated in the nanocomposite to stabilize Ag2S nanoparticles and interact strongly with the glucose moiety of arbutin (AR) and ascorbyl glucoside (AA2G), two important ingredients in whitening lotion products. The modified electrode was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) and cyclic voltammetry and used for the simultaneous analysis of hydroquinone (HQ), AR, and AA2G. The electrode showed excellent electrocatalysis towards the analytes by shifting the anodic peak potential to a negative direction with ≈5-fold higher current. The sensor displayed a linearity of 0.91–27.2 μM for HQ, 0.73–14.7 μM for AR, and 1.18–11.8 μM for AA2G, without cross-interference. A detection limit was 0.4 μM for HQ, 0.1 μM for AR, and 0.25 μM for AA2G. The sensor was applied to determine HQ, AR, and AA2G spiked in the whitening lotion sample with excellent recovery. The measured concentration of each analyte was comparable to that of the high performance liquid chromatographic (HPLC) method.

Reinforcing Effects of Poly(D-Lactide)-g-Multiwall Carbon Nanotubes on Polylactide Nanocomposites

2015 ◽  
Vol 15 (10) ◽  
pp. 8086-8092 ◽  
Author(s):  
Jeong Hee Yang ◽  
Jae Yun Lee ◽  
In-Joo Chin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Testing Machine ◽  
Multiwall Carbon Nanotubes ◽  
Hydroxyl Groups ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Polylactide (PLA) nanocomposites with multi-walled carbon nanotubes (MWNTs) grafted with poly(L-lactide) or poly(D-lactide) were prepared by solution casting, and their thermal and mechanical properties were evaluated. MWNTs containing hydroxyl groups were treated by ring-opening polymerization of either L-lactide or D-lactide. Fourier transform infrared spectroscopy confirmed that the MWNT surfaces had been modified by the PLLA or PDLA chains. The thermal properties were measured by differential scanning calorimetry and thermogravimetric analysis. The mechanical properties were examined using a universal testing machine. The morphology of the fractured surfaces of the PLA nanocomposites was observed by scanning electron microscopy and transmission electron microscopy. PDLA-g-MWNTs were dispersed more uniformly compared to PLLA-g-MWNTs in the PLA matrix. The incorporation of PDLA-g-MWNTs greatly improved the tensile strength of the nanocomposites regardless of the contents. Thermal analysis revealed different characteristics at specific composites depending on the type of modification.

Synthesis, Characterization and Magnetic Properties of Defective Nitrogen-Doped Multiwall Carbon Nanotubes Encapsulating Ferromagnetic Nanoparticles

2014 ◽  
Vol 28 ◽  
pp. 39-49 ◽  
Author(s):  
María Luisa García-Betancourt ◽  
Yadira Vega-Cantu ◽  
Sofía M. Vega-Díaz ◽  
Aaron Morelos-Gómez ◽  
Nestor Perea-López ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Magnetic Properties ◽  
Metallic Nanoparticles ◽  
Gas Flow ◽  
Multiwall Carbon Nanotubes ◽  
Chemical Vapor ◽  
Nitrogen Doped ◽  
Morphological Defects ◽  
Multi Walled Carbon Nanotubes

Nitrogen-doped multi-walled carbon nanotubes (CNxMWNTs) with multiple morphological defects were produced using a modified chemical vapor deposition (CVD) method. In a typical CNxMWNTs synthesis by CVD, an acetone trap is used to catch organic by-products from pyrolysis. In the present work, an aqueous solution of NaCl (26.82 wt%) was used in the trap, instead of acetone. Carbon nanotubes with sharp tips and lumps were found in the products. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy showed the formation of nanoparticles of different shapes inside the nanotubes. The electronic and magnetic properties were studied using a physical properties measurement Evercool system (PPMS). With this simple change in the CVD-trap, it is possible to control the morphology of carbon nanotubes and metallic nanoparticles. Differences in gas flow are proposed as a possible mechanism to produce these changes in both nanoparticles and CNxMWNTs.

CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO

2011 ◽  
Vol 10 (01n02) ◽  
pp. 23-28
Author(s):  
RAVI BHATIA ◽  
V. PRASAD ◽  
M. REGHU
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
High Degree

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.

Development of an HPLC method for measuring orally administered 1-substituted 2-alkyl-3-hydroxypyrid-4-one iron chelators in biological fluids

1990 ◽  
Vol 36 (1) ◽  
pp. 5-8 ◽  
Author(s):  
J G Goddard ◽  
G J Kontoghiorghes
Keyword(s):  
High Performance ◽  
Biological Fluids ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Hplc Method ◽  
Iron Chelators ◽  
Serum Samples ◽  
Thalassemic Patient ◽  
Serum And Urine

Abstract "High-performance" liquid-chromatographic (HPLC) methods have been developed for identifying 1-substituted 2-alkyl-3-hydroxypyrid-4-one iron chelators in serum and urine. Ion pairing with heptane- or octanesulfonic acid in pH 2.0-2.2 phosphate buffer and reversed-phase chromatography were required to separate these compounds from endogenous compounds in both biological fluids. In both the 2-methyl and 2-ethyl series of 1-substituted compounds (H, methyl, ethyl, or propyl) the elution times increased in accordance with the n-octanol/water partition coefficients (propyl greater than ethyl greater than H greater than methyl). Urine samples were filtered (0.4 microns pore size) and injected either undiluted or after dilution with elution buffer. After the addition of internal standard, the plasma or serum samples were deproteinized by treatment with HCIO4, 0.5 mol/L, centrifuged, and the supernates were injected directly onto the HPLC. Using these procedures, we could identify 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in the serum and urine of a thalassemic patient who had received a 3-g dose of the drug and in the urine of other patients who had received the same dose. One or more possible metabolites were also observed in the chromatograms of both urine and serum. The 24-h urinary output of L1 (0.22-2.37 g) and iron (10.6-71.5 mg) varied but there was no correlation between the two with respect to quantity or concentration. Instead, urinary iron output was higher in patients with a greater number of transfused units of erythrocytes. This is the first study in humans to show that L1 is absorbed from the gut, enters the circulation, and is excreted in the urine.

scholarly journals Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Jung-Eun Park ◽  
Yong-Seok Jang ◽  
Tae-Sung Bae ◽  
Min-Ho Lee
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Sol Gel ◽  
Pure Titanium ◽  
Cell Proliferation And Differentiation ◽  
Transmission Electron ◽  
Proliferation And Differentiation ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

scholarly journals A Simple and Sensitive HPLC Method for Simultaneous Analysis of Nabumetone and Paracetamol in Pharmaceutical Formulations

2011 ◽  
Vol 8 (s1) ◽  
pp. S41-S46
Author(s):  
Prafulla Kumar Sahu ◽  
M. Mathrusri Annapurna ◽  
Dillipkumar Sahoo
Keyword(s):  
High Performance ◽  
Internal Standard ◽  
Pharmaceutical Formulations ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Simultaneous Estimation ◽  
Aqueous Acetic Acid ◽  
Linear Calibration ◽  
Acceptance Range ◽  
Liquid Chromatographic

This paper describes a high-performance liquid chromatographic method for simultaneous estimation of nabumetone and paracetamol in binary mixture. The method was based on RP-HPLC separation and quantitation of the two drugs on hypersil C-18 column (250 mm × 4.6 mm) using a mobile phase consisting of acetonitrile and 0.05% aqueous acetic acid (70:30v/v) at flow rate of 1 mL min-1. Quantitation was achieved with PDA detector at 238 nm based on peak area with linear calibration curves at concentration ranges 5-25 µg mL-1for both the drugs. Naproxen sodium was used as internal standard. The method has been successively applied to pharmaceutical formulation. No chromatographic interference from the tablet excipients was found. The method was validated in terms of precision, robustness, recovery and limits of detection and quantitation. The intra and inter-day precision and accuracy values were in the acceptance range as per ICH guidelines.

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