Thermal Analysis of Herbal Drugs
Ravindra Kumar Pandey, Shiv Shankar Shukla, Amber Vyas, Vishal Jain, Parag Jain, Shailendra Saraf in Fingerprinting Analysis and Quality Control Methods of Herbal Medicines, 2018
Thermogravimetric analysis (TGA) is the most widely used thermal method. It is based on the measurement of the mass loss of material as a function of temperature. In thermogravimetry, a continuous graph of mass change against temperature is obtained when a substance is heated at a uniform rate or kept at a constant temperature. A plot of mass change versus temperature (T) is referred to as the thermogravimetric curve (TG curve). For the TG curve, we generally plot mass (m) decreasing downward on the y axis (ordinate), and temperature (T) increasing to the right on the x axis (abscissa). Sometimes we may plot time (t) in place of T. A TG Curve helps in revealing the extent of the purity of analytical samples and in determining the mode of their transformations within a specified range of temperature (Ma et al., 2017).
Thermal Analysis
Adorjan Aszalos in Modern Analysis of Antibiotics, 2020
The technique of thermogravimetric analysis [1,3,4] is that of constantly weighing a sample as its temperature is either held constant or linearly raised. Typically, the amount of sample is of the order of 5–30 mg. The atmosphere surrounding the sample can be controlled as to the type of gas (air, oxygen, and nitrogen, for example), the humidity of the gas, and whether the gas is static or flowing at a specific velocity. Several different designs are available. In one design, a small oven is moved into a position nearly surrounding the sample; in another design, the balance, including the sample, is moved on a track so that the sample is enclosed within an oven. Both types appear to be suitable.
Herbal Drug Development: Challenges and Opportunities
Megh R. Goyal, Durgesh Nandini Chauhan in Plant- and Marine-Based Phytochemicals for Human Health, 2018
The chemical and physical changes in product are studied by thermogravimetric analysis (TGA), differential thermal analysis, and differential scanning calorimetry. It helps to study pre-formulation or drug-excipient compatibility. TGA is operated under controlled conditions to analyze alcohol content in various herbal formulations such as Asava and Arishta and metals in Bhasmas.82
Mercury(II) decontamination using a newly synthesized poly(acrylonitrile-acrylic acid)/ammonium molybdophosphate composite exchanger
Published in Toxin Reviews, 2022
Adel A. El-Zahhar, Abubakr M. Idris
In this study, it has been proposed to utilize the potentials of hybridization of organic and inorganic compounds, as discussed above, for Hg(II) removal from aqueous solution. Toward this end, a novel ion-exchanger composite based on hybridization of AMP with co-polymer poly-acrylonitrile-acrylic acid to obtain P(AN-AA)/AMP was synthesized. The functional groups on the surface of the newly proposed composite were identified using Fourier transform infrared spectrometry (FTIR). The surface morphology of the composite was also examined throughout scanning electron microscopy (SEM). Brunauer–Emmett–Teller (BET) analysis was carried out as well to study the surface properties of the composite. In addition, thermogravimetric analysis (TGA) was carried out to evaluate the thermal stability. Furthermore, parameters presumed to be controlling the adsorption process were studied and the optimum conditions of pH, time, adsorbent dose, and ion concentration were assigned.
EM-test for homogeneity in a two-sample problem with a mixture structure
Published in Journal of Applied Statistics, 2020
Guanfu Liu, Yuejiao Fu, Jianjun Zhang, Xiaolong Pu, Boying Wang
For the class of location mixtures of distributions, i.e. the component distributions differ only in the location parameters, there are also a large number of applications. For example, Roeder [32] applied location mixture of normal distributions to analyze sodium-lithium countertransport activity in red blood cells, and Loisel et al. [23] used location mixture of normal distributions to fit the total number of grains per plant. The location mixture of logistic distributions was used by Naya et al. [25] to study the thermogravimetric analysis trace. In Example 4.4.2 of Lawless [17], the author applied the location mixture of extreme value distributions to fit the logarithm of the number of cycles to failure for a group of 60 electrical appliances. More applications can be seen in [17,24].
Poly-β-Cyclodextrin-coated neodymium-containing copper sulphide nanoparticles as an effective anticancer drug carrier
Published in Journal of Microencapsulation, 2022
Archana Sumohan Pillai, Aleyamma Alexander, Govindaraj Sri Varalakshmi, Varnitha Manikantan, Bose Allben Akash, Israel V. M. V. Enoch
The obtained pol-CD-coated NPs were analysed for their grain size, crystal phase, dislocation density employing X-ray diffraction (Bruker D8-Advance) using Cu kα (λ = 0.154 Å) radiation at angles 10–80°. The dimensions of the NPs were determined using high-resolution transmission electron microscope (HR TEM–Jeol/JEM 2100). The average hydrodynamic size was done using Dynamic light-scattering (DLS) measurement (Malvern Nano Zs90 Zetasizer). Energy dispersive X-ray (EDX) instrument Jeol/JEM 2100 was employed to confirm the composition of the NPs. The magnetic property was followed on a Lake-shore 7410 Vibrating Sample Magnetometer (VSM). Thermogravimetric analysis (TA instruments, USA Model SDT Q600) was done to calculate the amount and rate of mass loss of the samples varying with the temperature. The quantitative atomic composition and the electronic state of the elements was determined using a Thermofisher Scientific Model Nexsa bas X-ray photoelectron spectroscopy (XPS).
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