Chemometrics
Mostrando 13-24 de 138 artigos, teses e dissertações.
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13. EXPERIMENTO DIDÁTICO DE QUIMIOMETRIA PARA CLASSIFICAÇÃO DE ÓLEOS VEGETAIS COMESTÍVEIS POR ESPECTROSCOPIA NO INFRAVERMELHO MÉDIO COMBINADO COM ANÁLISE DISCRIMINANTE POR MÍNIMOS QUADRADOS PARCIAIS: UM TUTORIAL, PARTE V
A teaching experiment on supervised pattern recognition in chemometrics was proposed in this tutorial to introduce partial least squares discriminant analysis (PLS-DA). A new approach of the experiment published in the first tutorial of this series was revisited and employed to the classification of edible vegetable oils. The spectra of olive, canola, soybea
Quím. Nova. Publicado em: 2020-03
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14. RP-HPLC and LC–MS–MS determination of a bioactive artefact from Ipomoea pes-caprae extract
Abstract Solvents play important and critical role in natural product chemistry and could generate artefacts during the extraction and purification of metabolites from a biological matrix. This study aimed to correlate the chromatographic profile with biological activity of Ipomoea pes-caprae (L.) R. Br., Convolvulaceae, extracts obtained with hydroethanolic
Rev. bras. farmacogn.. Publicado em: 09/12/2019
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15. Vibrational Spectroscopy and Chemometrics in Forensic Chemistry: Critical Review, Current Trends and Challenges
The present manuscript makes an extensive review of the scientific approaches developed in the last decade involving infrared and Raman spectroscopy combined with chemometrics for solving several issues in the investigation of the most relevant forensic traces, such as questioned documents and currency, explosives, gunshot residues, illicit drugs and body fl
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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16. High Throughput Mass Spectrometry Platform for Prospecting High Value Chemicals from Bioconversion of Glycerin
The use of bioprocess to convert low valued biomass or agroindustrial byproducts into high-value chemicals is an emerging area. However, laboratories usually use outdated analytical techniques to identify bioproducts, losing valuable information, such as the identification of unexpected compounds. In this work, we presented a successful systematic and modern
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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17. Headspace analysis and characterisation of South African propolis volatile compounds using GCxGC–ToF–MS
ABSTRACT Propolis also known as "bee glue or bee resin" is a resinous mixture of bee saliva or bee wax and exudate from tree trunks and flowers, produced by honeybees. The composition of propolis varies depending on the vegetation the bees can access. It is therefore expected that propolis obtained from various localities may have different chemical profiles
Rev. bras. farmacogn.. Publicado em: 26/08/2019
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18. CHEMOMETRIC TOOLS AND FTIR-ATR SPECTROSCOPY APPLIED IN MILK ADULTERATED WITH CHEESE WHEY
Brazilian law forbids the addition of cheese whey in milk. However, adulteration with cheese whey is one of the most applied fraud due to its low cost. The detection of this fraud is the quantification of Caseinomacropeptide (CMP). The CMP is a constituent of the whey that can be used as adulteration marker. Thus, an analytical method capable of identifying
Quím. Nova. Publicado em: 02/05/2019
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19. An overview of the Brazilian contributions to Green Analytical Chemistry
Abstract: Green Analytical Chemistry (GAC) is a research field that seeks for more sustainable analytical approaches to minimize the toxicity and amounts of wastes without hindering the analytical performance. This is a trend in Analytical Chemistry worldwide and because of the diversity of innovations on this subject, Brazil stands out as the third in the l
An. Acad. Bras. Ciênc.. Publicado em: 18/04/2019
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20. Quality assessment of the manufacture of new ripened soft cheese by Geotrichum candidum: physico-chemical and technological properties
Abstract A new type of ripened soft cheese by Geotrichum candidum was manufactured with pasteurized milk from Jersey and Holstein cow breeds. The physico-chemical (moisture, pH, acidity, protein, lipids and ash) and technological parameters (proteolysis, texture profile and color) during 21 days of ripening cheese (surface, center and whole), were evaluated
Food Sci. Technol. Publicado em: 16/04/2018
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21. HR-MAS NMR Allied to Chemometric on Hancornia speciosa Varieties Differentiation
This work describes the potential of chemometric analyses applied to 1H high-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR) data for the chemotaxonomic investigation of Hancornia speciosa (Apocynaceae) varieties. This plant, popularly known as mangaba, has a complex morphological differentiation and thus chemical analyses can be u
J. Braz. Chem. Soc.. Publicado em: 2018-04
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22. Applying chemometrics to predict metallurgical niobium recovery in weathered ore
Abstract Niobium metallurgical recovery measures how much of the metal content in the ore is separated in the concentrate after the mineral processing stages. This information can be obtained through laboratory tests with ore samples obtained during drilling. Thereunto, representative ore samples are subjected to tests mimicking the ore concentration process
REM, Int. Eng. J.. Publicado em: 2018-03
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23. Application of Response Surface Modeling and Chemometrics Methods for the Determination of Ofloxacin in Human Urine Using Dispersive Liquid-Liquid Microextraction Combined with Spectrofluorimetry
Dispersive liquid-liquid microextraction (DLLME) and spectrofluorimetry, coupled with chemometrics methods, are proposed in this work for the pre-concentration and determination of ofloxacin concentration in spiked human urine. Chloroform and acetonitrile were selected as the extraction and dispersive solvents by the one-variable-at-a-time process. The Box-B
J. Braz. Chem. Soc.. Publicado em: 2017-12
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24. Nuclear Magnetic Resonance (1.40 T) and Mid Infrared (FTIR-ATR) Associated with Chemometrics as Analytical Methods for the Analysis of Methyl Ester Yield Obtained by Esterification Reaction
In this work, we compared 1.40 T nuclear magnetic resonance (NMR) to 7.05 T (60 and 300 MHz for proton, respectively), and mid-infrared with attenuated total reflectance (FTIR-ATR), associated with chemometrics methods, for the quantification of the reaction yield during esterification of fatty acids with methanol. The results showed that the integrated inte
J. Braz. Chem. Soc.. Publicado em: 2017-10