Acid Digestion
Mostrando 1-12 de 1129 artigos, teses e dissertações.
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1. Atomic Absorption Spectrometry as an Alternative to Determine the Presence of Gold Nanoparticles on or in Silica Matrix
Two different gold-silica-based nanomaterials were prepared: (i) silica-supported gold nanoparticles (AuNP/SiO2); and (ii) gold-silica core-shell nanoparticles (AuNP@SiO2). Three strategies for sample treatment (S), consisting in acid treatments, were employed: (S1) HNO3; (S2) HNO3 + HCl; and (S3) HF + HNO3 + HCl, applying microwave oven digestion for S2 and
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Solventes eutéticos naturais profundos (NADES) no preparo de amostras de rocha fosfática e suplemento mineral para determinação elementar por técnicas de plasma
Natural deep eutectic solvents (NADES) based on xylitol, citric acid, and malic acid were synthesized and used in ultrasound-assisted extraction (UAE) and heating-bath extraction of phosphate rock and mineral supplement samples. Arsenic, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, P and Zn were determined by inductively coupled plasma mass spectrometry (ICP-MS) and i
Quím. Nova. Publicado em: 2021-06
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3. Microwave-Assisted Acid Digestion: Evaluation of Reaction Vessel Design and Performance
Nowadays, microwave-assisted procedures using closed vessels with thermal, chemical, and mechanical resistance are the state-of-the-art for efficient digestion of samples. Safety issues related to sample reactivity should be considered and analytical throughput is also a critical parameter. The choice of a specific vessel for a target application is not triv
J. Braz. Chem. Soc.. Publicado em: 2021-04
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4. Sample Preparation Using TMAH and Nitric Acid for Multielement Determination in Crustacean Samples by MIP OES
This study proposes a simple sample preparation procedure using tetramethylammonium hydroxide (TMAH) and nitric acid (HNO3) to determine Cr, Cu, Fe, K, Mg, Mn, and Zn concentrations in shrimp (Macrobrachium amazonicum) and crab (Ucides cordatus) samples from the Amazon region by microwave-induced plasma optical emission spectrometry (MIP OES). The sample sol
J. Braz. Chem. Soc.. Publicado em: 2021-03
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5. SEQUENTIAL MULTI-ELEMENT DETERMINATION OF TRACE-METALS IN BIODIESEL SAMPLES USING HR-CS FAAS
In this work the feasibility of sequential multi-element determination of Zn, Fe, Mg, Cu, Na, K, Cr, Al and Ca in biodiesel samples by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was investigated. Biodiesel samples obtained from different sources and different chemical processes were analysed. The samples were diluted w
Quím. Nova. Publicado em: 2021-02
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6. MAIN MINERALS AND ORGANIC COMPOUNDS IN COMMERCIAL ROASTED AND GROUND COFFEE: AN EXPLORATORY DATA ANALYSIS
Coffee is one of the most popular beverages in the world, however, little information is found regarding the mineral composition of commercial roasted and ground coffees (RG) and its correlation with organic bioactive compounds. 21 commercial Brazilian RG coffee brands - 9 traditional (T) and 12 extra strong (ES) roasted ones - were analyzed for the Cu, Ca,
Quím. Nova. Publicado em: 2021-01
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7. Multivariate Analysis: Use of Doehlert Design (DD) for Optimization of a Simple Sample Preparation Procedure for the Determination of Inorganic Constituents in Cocoa Beans Employing Microwave Acid Digestion and ICP OES
This study presents a microwave-assisted procedure for sample preparation of cocoa beans using diluted HNO3 with H2O2 for the determination of Ba, Ca, Cu, K, Mg, Mn, P, S, Sr and Zn by inductively coupled plasma optical emission spectrometry (ICP OES). Doehlert modified design was used for optimization of experimental condition, and the volume of H2O2 (0, 0.
J. Braz. Chem. Soc.. Publicado em: 2020-10
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8. Voltammetric Determination of Free and Total Manganese in Tea Infusions
Tea infusions are a source of mineral nutrients, including manganese. Although it is classified as an essential element, the excess of manganese is toxic for humans and its toxicity depends on its bioavailability. In this context, we propose a simple procedure to determine free and total manganese in black tea infusions by square-wave voltammetry (SWV). Free
J. Braz. Chem. Soc.. Publicado em: 2020-07
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9. Influence of in vitro gastrointestinal digestion on phytochemicals in pomegranate juice
Abstract Nowadays, healthy food is in vogue. The consumption of fresh fruits and vegetables has always been advised. Their health benefits are estimated based on the chemical composition without taking into account the possible transformations during digestion. Undoubtedly, those with the highest antioxidant content are highly favored. However, whether they
Food Sci. Technol. Publicado em: 2020-06
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10. Application of Mixture Design Using Diluted Acid for Extraction of Inorganic Components in Fruits of Casearia fasciculata and Determination by ICP OES: Evaluation by PCA and HCA
This study is the first to propose the simultaneous quantification of 10 elements in fruits of Casearia fasciculata by inductively coupled plasma optical emission spectrometry (ICP OES). A method of digestion using dilute nitric acid was optimized by mixture design for extraction of elements in the seed, peel, and pulp of Casearia fasciculata cultivated in t
J. Braz. Chem. Soc.. Publicado em: 2020-06
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11. Modeling and prediction of sulfuric acid digestion analyses data from PXRF spectrometry in tropical soils
ABSTRACT Sulfuric acid digestion analyses (SAD) provide useful information to environmental studies, in terms of the geochemical balance of nutrients, parent material uniformity, nutrient reserves for perennial crops, and mineralogical composition of the soil clay fraction. Yet, these analyses are costly, time consuming, and generate chemical waste. This wor
Sci. agric. (Piracicaba, Braz.). Publicado em: 04/11/2019
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12. Influence of in vitro gastrointestinal digestion on phytochemicals in pomegranate juice
Abstract Nowadays, healthy food is in vogue. The consumption of fresh fruits and vegetables has always been advised. Their health benefits are estimated based on the chemical composition without taking into account the possible transformations during digestion. Undoubtedly, those with the highest antioxidant content are highly favored. However, whether they
Food Sci. Technol. Publicado em: 28/10/2019