Coffee adulterant quantification by derivative thermogravimetry and chemometrics analysis

2021 ◽  
Author(s):  
Lucas H. Pereira ◽  
Tiago A. Catelani ◽  
Éderson D.’M. Costa ◽  
Jerusa S. Garcia ◽  
Marcello G. Trevisan
Keyword(s):  
Derivative Thermogravimetry

scholarly journals Struvite Grown in Gel, Its Crystal Structure at 90 K and Thermoanalytical Study

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 89 ◽  
Author(s):  
Jolanta Prywer ◽  
Lesław Sieroń ◽  
Agnieszka Czylkowska
Keyword(s):  
Thermal Analysis ◽  
Sodium Metasilicate ◽  
X Ray Diffraction ◽  
Gel Growth ◽  
Growth Technique ◽  
Thermoanalytical Study ◽  
X Ray ◽  
Cell Parameters ◽  
Thermal Analysis Techniques ◽  
Derivative Thermogravimetry

In this article, we report the crystallization of struvite in sodium metasilicate gel by single diffusion gel growth technique. The obtained crystals have a very rich morphology displaying 18 faces. In this study, the habit and morphology of the obtained struvite crystals are analyzed. The crystals were examined and identified as pure struvite by single X-ray diffraction (XRD). The orthorhombic polar noncentrosymmetric space group Pmn21 was identified. The structure of the crystal was determined at a temperature of 90 K. Our research indicates a lack of polymorphism, resulting from the temperature lowering to 90 K, which has not been previously reported. The determined unit cell parameters are as follows a = 6.9650(2) Å, b = 6.1165(2) Å, c = 11.2056(3) Å. The structure of struvite is presented here with a residual factor R1 = 1.2% at 0.80 Å resolution. We also present thermoanalytical study of struvite using thermal analysis techniques such as thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA).

Adsorption of the harmful hormone ethinyl estradiol inside hydrophobic cavities of CTA+ intercalated montmorillonite

2016 ◽  
Vol 74 (3) ◽  
pp. 663-671 ◽  
Author(s):  
A. E. Burgos ◽  
Tatiana A. Ribeiro-Santos ◽  
Rochel M. Lago
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
High Efficiency ◽  
Interlayer Space ◽  
Ethinyl Estradiol ◽  
Significant Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrophobic Cavity ◽  
Adsorption Capacities ◽  
Derivative Thermogravimetry

Hydrophobic cavities produced by cetyltrimethylammonium cation (CTA+) exchanged and trapped in the interlayer space of montmorillonite were used to remove the harmful hormone contaminant ethinyl estradiol (EE2) from water. X-ray diffraction, thermogravimetry/derivative thermogravimetry, elemental analysis (carbon, hydrogen, nitrogen), Fourier transform infrared, scanning electron microscopy/energy dispersive spectroscopy, Brunauer–Emmett–Teller and contact angle analyses showed that the intercalation of 9, 16 and 34 wt% CTA+ in the montmorillonite resulted in the d001 expansion from 1.37 to 1.58, 2.09 and 2.18 nm, respectively. EE2 adsorption experiments showed that the original clay montmorillonite does not remove EE2 from water whereas the intercalated composites showed high efficiency with adsorption capacities of 4.3, 8.8 and 7.3 mg g−1 for M9CTA+, M16CTA+ and M34CTA+, respectively. Moreover, experiments with montmorillonite simply impregnated with cetyltrimethylammonium bromide showed that the intercalation of CTA+ to form the hydrophobic cavity is very important for the adsorption properties. Simple solvent extraction can be used to remove the adsorbed EE2 without significant loss of CTA+, which allows the recovery and reuse of the adsorbent for at least five times.

KINETIC MODEL FOR THERMAL DEHYDROCHLORINATION OF CHLORINATED NATURAL RUBBER WITH DIFFERENT CHLORINE CONTENT

2014 ◽  
Vol 87 (2) ◽  
pp. 370-382
Author(s):  
Jing Chen ◽  
Lanzhen He ◽  
Yasheng Chen ◽  
Jieping Zhong ◽  
Canzhong He ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Oxidative Degradation ◽  
Storage Conditions ◽  
Chlorine Content ◽  
Heating Process ◽  
Lower Temperature ◽  
Novel Model ◽  
Derivative Thermogravimetry ◽  
Selection Of ◽  
Thermo Oxidative Degradation

ABSTRACT A novel model for calculating dehydrochlorination kinetics at a lower temperature of chlorinated natural rubber (CNR) is presented. It has been observed that dehydrochlorination is complex and involves three different stages. A model that accounts for dehydrochlorination at lower temperature is proposed. The kinetic parameters are obtained from dehydrochlorination experiments at 60–90 °C. The results of the kinetic calculation show that the apparent activation energy decreases with an increment of chlorine content. Higher chlorine content CNR makes it easier to remove hydrochloric acid when heated, but its dehydrochlorination rate affected by temperature is significantly less than that of the sample with a lower chlorine content. The thermogravimetric/derivative thermogravimetry results show that the beginning temperature of thermo-oxidative degradation rises with the increment of chlorine content. During the heating process, the higher chlorine content CNR is more stable than the lower one. The results suggest the storage conditions and basis for selection of appropriate temperature for the preparation of CNR from latex.

scholarly journals EVALUATION THERMOANALYTICAL OF WHEAT FLOUR FORTIFIED WITH FOLIC ACID AND FERROUS SULPHATE

2009 ◽  
Vol 06 (12) ◽  
pp. 47-50
Author(s):  
Eliane Gonçalves ARAÚJO ◽  
Nedja Suely FERNANDES
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Folic Acid ◽  
Wheat Flour ◽  
Ferrous Sulphate ◽  
Scanning Calorimetry ◽  
Iron Sulphate ◽  
Derivative Thermogravimetry

In this work wheat flour aditived with folic acid and iron sulphate was evaluated by Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and differential scanning calorimetry (DSC) for evaluation of the thermal stability. The results obtained showed that the samples of wheat flour have similar behaviour.

scholarly journals Thermal behaviour study of solid state compounds of manganese (II), zinc (II) and lead (II) with cinnamic acid

1998 ◽  
Vol 23 (0) ◽  
pp. 09-16
Author(s):  
Marco Aurélio da Silva CARVALHO FILHO ◽  
Massao IONASHIRO
Keyword(s):  
Thermal Stability ◽  
Aqueous Solution ◽  
Differential Scanning Calorimetry ◽  
Cinnamic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Manganese Zinc ◽  
Behaviour Study ◽  
Derivative Thermogravimetry

Compounds of cinnamic acid with manganese, zinc and lead have been prepared in aqueous solution. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), X-ray diffraction and complexometry have been used in the characterization as well as in the study of the thermal stability and interpretation concerning the thermal decomposition.

Co-combustion Characteristics and Kinetics Behavior of Torrefied Sugarcane Bagasse and Lignite

2021 ◽  
Vol 10 (4) ◽  
pp. 737-746
Author(s):  
Ukrit Samaksaman ◽  
Kanit Manatura
Keyword(s):  
Thermogravimetric Analysis ◽  
Physicochemical Properties ◽  
Burning Rate ◽  
Sugarcane Bagasse ◽  
Combustion Characteristics ◽  
Firing Process ◽  
Combustion System ◽  
Heating Value ◽  
Kinetics Of ◽  
Derivative Thermogravimetry

The co-combustion characteristics and kinetics of torrefied sugarcane bagasse (TB), lignite (L), and their blended samples were experimentally investigated using thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG)based on the Coats-Redfern method for kinetic estimation.Their physicochemical properties were also investigated.Raw bagasse was thermally treated in a laboratory-scale torrefactor at 275 °C with a torrefaction time of 60 min under an inert nitrogen environment.Then, the torrefied bagasse was blended with Thai lignite as a co-fuel at ratios of 50:50 (TB50L50), 70;30(TB70L30), and 90:10 (TB90L10), respectively. Torrefaction improved the fuel properties and heating value of the raw bagasse as well as reducing the O/C and H/C ratios.In addition, the blending of torrefied bagasse with lignite improved the combustion behavior.The TGA and DTG results indicated that the ignition and burnout temperatures stepped downwards with different increasing ratios of torrefied bagasse.The co-combustion behavior at the maximum burning rate showed that the burnout temperatures of TB50L50, TB70L30, and TB90L10 were 532, 529, and 528 °C, respectively, indicating a slight decrease with an increasing torrefied bagasse blending ratio.These results were sufficient to provide comprehensive guidelines in terms of the design and operation of the combustion system for adding torrefied bagasse into the co-firing process.

scholarly journals Assessment of Residual Solvent and Drug in PLGA Microspheres by Derivative Thermogravimetry

Pharmaceutics ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 626
Author(s):  
Hyunjin Shim ◽  
Hongkee Sah
Keyword(s):  
Evolved Gas Analysis ◽  
Time Derivative ◽  
Ethyl Formate ◽  
Gas Analysis ◽  
Specific Information ◽  
Plga Microspheres ◽  
Residual Solvent ◽  
Polymeric Matrices ◽  
Quality Control Tool ◽  
Derivative Thermogravimetry

Thermogravimetry does not give specific information on residual organic solvents in polymeric matrices unless it is hyphenated with the so-called evolved gas analysis. The purpose of this study was to apply, for the first time, derivative thermogravimetry (DTG) to characterize a residual solvent and a drug in poly-d,l-lactide-co-glycolide (PLGA) microspheres. Ethyl formate, an ICH class 3 solvent, was used to encapsulate progesterone into microspheres. DTG provided a distinct peak, displaying the onset and end temperatures at which ethyl formate started to evolve from to where it completely escaped out of the microspheres. DTG also gave the area and height of the solvent peak, as well as the temperature of the highest mass change rate of the microspheres. These derivative parameters allowed for the measurement of the amount of residual ethyl formate in the microspheres. Interestingly, progesterone affected not only the residual solvent amount but also these derivative parameters. Another intriguing finding was that there was a linear relationship between progesterone content and the peak height of ethyl formate. The residual solvent data calculated by DTG were quite comparable to those measured by gas chromatography. In summary, DTG could be an efficient and practical quality control tool to evaluate residual solvents and drugs in various polymeric matrices.

scholarly journals Application of Thermal Methods to Analyze the Properties of Coffee Silverskin and Oil Extracted from the Studied Roasting By-Product

2020 ◽  
Vol 10 (24) ◽  
pp. 8790
Author(s):  
Agata Górska ◽  
Rita Brzezińska ◽  
Magdalena Wirkowska-Wojdyła ◽  
Joanna Bryś ◽  
Ewa Domian ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Reliable Data ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Modulated Differential Scanning Calorimetry ◽  
Coffee Silverskin ◽  
Derivative Thermogravimetry ◽  
Coffee Roasting

The aim of the study was to characterize the thermal properties of coffee silverskin and fat extracted from the material by using differential scanning calorimetry, modulated differential scanning calorimetry and thermogravimetry/derivative thermogravimetry. Additionally, the thermokinetic parameters, oxidative stability and fatty acid composition of the extracted oil were defined. Thermal decomposition of the studied coffee roasting by-product under oxygen occurred in three defined stages. The most significant changes in weight were observed in the region of 200–500 °C and correspond to polysaccharide decomposition. These results are in agreement with the data obtained from the differential scanning calorimetry curve. On the curve course of silverskin, two main exothermic peaks can be observed with a maximum at 265 and 340 °C. These exothermic events represent the transitions of hemicellulose and cellulose. Fat extracted from silverskin turned out to be a source of polyunsaturated fatty acids with the recommended n-6 to n-3 ratio reaching the value 4:1. The studied fat was characterized by low oxidative stability. Considering the obtained results, it can be stated that thermal analysis can provide fast and reliable data concerning the composition and properties of coffee silverskin and coffee silverskin oil.

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