Samples Preparation
Mostrando 1-12 de 858 artigos, teses e dissertações.
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1. Simultaneous GC-NCI-MS Determination of Persistent Organic Pollutants and Current-Use Pesticides in Breast Milk Samples
To preserve human health, persistent organic pollutants (POPs) and current-use pesticides (CUPs) should be monitored in fatty tissues, including breast milk. Therefore, this study aimed to optimize sample preparation conditions using a 32 factorial design for the determination of POPs and CUPs by gas chromatography coupled to mass spectrometry with negative
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Simple Spectrophotometric Determination of Iron in Diesel Oil after Sample Preparation Employing Extraction Induced by Emulsion Breaking
This work reports the development of a simple and fast method for the spectrophotometric determination of Fe in diesel oil using the classic reaction with 1,10-phenanthroline after its extraction induced by emulsion breaking (EIEB). The extraction parameters of EIEB were optimized (concentration of HNO3 and Triton X-100® in the emulsifying solution) as well
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. Determinação de etil-glicuronídeo e etil-sulfato em sangue por UPLC-MS/MS: aplicação clínica em vítimas de trauma
We developed a UPLC-MS/MS method for the quantification of the ethanol metabolites ethyl-glucuronide (EtG) and ethyl-sulfate (EtS) in blood samples. Sample preparation was a protein precipitation with acetonitrile 0.1% formic acid containing internal standards (IS) 0.5 µg mL-1 EtG-D5 and EtS-D5. Chromatographic separation was performed in a fluoro-phenyl co
Química Nova. Publicado em: 2022
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4. An Eco-Friendly Proposal by Integrating Chromatographic Fingerprinting and Multivariate Control Chart in a Non-Target Analysis to Evaluate Grape Juices from Different Farming Practices
A potential eco-friendly method without organic solvents is presented by integrating a chromatographic fingerprint and multivariate control chart based on Q residuals to differentiate grape juices from different farming practices. The sample preparation was only water dilution, and the mobile phase was water acidified with sulfuric acid, which can be readily
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. Colorimetric analysis of dental porcelains: effects of the background color
Abstract This study evaluated how the background (white or gray) affects the color parameter measurements and color difference calculations (∆Eab and ∆E00) of dental ceramics. Disc-shaped feldspathic ceramic specimens were prepared with two shades (enamel and dentin) and stained in red wine (7-day immersion). A spectrophotometer was used to perform color
Cerâmica. Publicado em: 2022
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6. Determination of Ethyl Carbamate in Commercial Sweetened Sugar Cane Spirit by ESI-MS/MS Using Modified QuEChERS and 18-Crown-6/Trifluoroacetic Acid Spiking Additives
A fast, sensitive, and selective direct injection electrospray tandem mass spectrometry (DI ESI MS/MS) method that is able to quantify ethyl carbamate in commercial sweetened sugar cane spirit is described. The preparation method uses a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) with potassium carbonate added to sweetened sugar cane
Journal of the Brazilian Chemical Society. Publicado em: 2022
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7. Optimization of potato starch gel formulation as green alternative of animal-sourced gelatin
Abstract This study was aimed at optimization of potato starch gel preparation process by response surface methodology and various process parameters were optimized for textural, gelation and sensory properties. 3D response surface and contour plots showed that independent variables, such as extraction time, extraction temperature and potato starch concentra
Food Sci. Technol. Publicado em: 2021-09
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8. Development of Analytical Method for Determination of Inorganic Constituents in Powder Refreshment Using Dilute Mineral Acids and Detection by ICP OES
An analytical method for multi-elementary determination in powder refreshment, based on sample digestion using dilute mineral acids and detection by inductively plasma coupled optical emission spectrometry (ICP OES) is proposed. Chemometric tools, such as fractional factorial design and principal component analysis (PCA) and hierarchical cluster analysis (HC
J. Braz. Chem. Soc.. Publicado em: 2021-07
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9. Prevalence and level of Salmonella spp. Contamination on selected pathways of preparation and cooking of fried chicken at the household level
Abstract Homemade foods have been reported as an important contributor to some foodborne outbreaks. This study determined the prevalence and number of Salmonella spp. on selected pathways of fried chicken preparation and cooking at the household level and investigated their antimicrobial resistance. Salmonella serovar was confirmed by polymerase chain reacti
Food Sci. Technol. Publicado em: 2021-06
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10. Reduced Graphene Oxide/Ruthenium Oxide Hexacyanoferrate Nanocomposite for Electrochemical Determination of Ethanol in Commercial Samples
Reduced graphene oxide/ruthenium oxide hexacyanoferrate (rGO/RuOHCF) modified electrode showed synergic activity between the materials attested by the increase of electrochemical current and stability. The preparation of the nanocomposite was made by a simple two-step electrochemical approach. The material structure was characterized by spectroscopic techniq
J. Braz. Chem. Soc.. Publicado em: 2021-06
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11. Individuals with untreated psychiatric disorders and suicide in the COVID-19 era
Reduced graphene oxide/ruthenium oxide hexacyanoferrate (rGO/RuOHCF) modified electrode showed synergic activity between the materials attested by the increase of electrochemical current and stability. The preparation of the nanocomposite was made by a simple two-step electrochemical approach. The material structure was characterized by spectroscopic techniq
Braz. J. Psychiatry. Publicado em: 2021-06
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12. 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