Direct Determination
Mostrando 1-12 de 711 artigos, teses e dissertações.
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1. Use of Direct Aqueous Injection and Solid Phase Extraction Coupled with Hydrophilic Interaction Chromatography to Analyze Haloacetic Acids in Drinking Water Samples
In this study, two analytical methods were evaluated to determine haloacetic acids (HAAs) in drinking water samples. Direct aqueous injection (DAI) and solid phase extraction (SPE) were evaluated and determination was performed by liquid chromatography tandem mass spectrometry (LC-MS/MS) with a hydrophilic interaction chromatography (HILIC) analytical column
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. 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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3. Association of Anti-β1 and Anti-M2 Antibodies with Autonomic Nervous System Modulation in Patients with Chronic Chagas Cardiomyopathy
Abstract Background: Different immune mechanisms of myocardial damage involved in the pathophysiology of Chagas disease coexist with high titers of autoantibodies induced by T. cruzi . There are few studies in the literature about the adaptive role of anti-β1 and anti-M2 antibodies in chronic Chagas cardiomyopathy (CCC). Objectives: To evaluate the associ
International Journal of Cardiovascular Sciences. Publicado em: 2022
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4. Development of a Simple and Fast Procedure Based on Acid Dilution for Determination of Macro and Microelements in Guarana-Based Beverages by ICP OES
A simple analytical procedure is proposed for the direct analysis of guarana-based beverages in order to determine nutrient elements by inductively coupled plasma optical emission spectrometry (ICP OES). A Box-Behnken design, combined with Derringer’s desirability function, was applied to the simultaneous optimization of the ICP OES radiofrequency (RF), sa
J. Braz. Chem. Soc.. Publicado em: 2021-07
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5. Evaluation of the Direct Interaction between Amino Acids and Glutathione-Coated CdTe Quantum Dots and Application in Urinalysis for Histidine Determination
The present work aimed to direct amino acid (AA) sensing by quantum dots (QD) and development of an analytical method for potential fast clinical tests. Notably, AA with a positive charge or neutral polar chains, namely L-histidine (His) and L-threonine (Thr), responded to glutathione-coated CdTe (GSH-CdTe) (ΔF ≤ 90%, variation of fluorescence intensity).
J. Braz. Chem. Soc.. Publicado em: 2021-03
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6. Direct Solid Sample Analysis of Medicinal Herbs for Determination of Ba, Cu, Ni, V and Zn by EDXRF
In this work, an analytical method for determination of Ba, Cu, Ni, V, and Zn, in medicinal herbs, through direct solid sample analysis by energy dispersive X-ray fluorescence spectrometry (EDXRF), was applied. Accuracy and precision (intra and inter day) of the analytical method were confirmed through analysis of certified reference material, tomato leaves
J. Braz. Chem. Soc.. Publicado em: 2021-01
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7. What to Expect for the New Year?
In this work, an analytical method for determination of Ba, Cu, Ni, V, and Zn, in medicinal herbs, through direct solid sample analysis by energy dispersive X-ray fluorescence spectrometry (EDXRF), was applied. Accuracy and precision (intra and inter day) of the analytical method were confirmed through analysis of certified reference material, tomato leaves
J. Braz. Chem. Soc.. Publicado em: 2021-01
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8. Determining Mercury in Sediment Samples by Extraction Using a Novel-Chelating Reagent Dithiothreitol (DTT) Followed by Cold Vapor Atomic Fluorescence Spectrometry (CV-AFS)
A new analytical protocol has been developed for the determination of mercury in surface sediments using dithiothreitol (DTT) as a new chelating reagent for the extraction. This protocol requires a small sample mass (250 mg), 4.0 mL of a 0.1 M (pH = 9.0) aqueous DTT solution, and sonication for 30 min, followed by cold vapor atomic fluorescence spectrometry
J. Braz. Chem. Soc.. Publicado em: 2020-12
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9. Electroanalytical Method for Determination of Trace Metals in Struvite Using Electrochemically Treated Screen-Printed Gold Electrodes
We present an electroanalytical method using square-wave anodic stripping voltammetry on electrochemically-treated screen-printed gold electrodes to the simultaneous determination of lead(II), copper(II) and mercury(II) in struvite (natural fertilizer produced from urine). Electrochemical treatment via cyclic voltammetry of the working electrodes increased s
J. Braz. Chem. Soc.. Publicado em: 2020-09
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10. DETERMINATION OF THE PESTICIDES IN WATER USED IN THE CULTURE AND PROCESSING OF POTATOES
The contamination of water bodies by pesticide residues through direct flow, leaching and other methods has motivated the development of analytical methods for the determination of these compounds in water. A vortex-assisted liquid-liquid microextraction method followed by gas chromatography coupled to mass spectrometry for the determination of anilazine, li
Quím. Nova. Publicado em: 2020-09
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11. Quantification of Glyphosate and AMPA by HPLC-ICP-MS/MS and HPLC-DAD: A Comparative Study
In this work, the direct determination methodology of glyphosate and aminomethylphosphonic acid (AMPA) by high performance liquid chromatography (HPLC) using inductively coupled plasma with triple quadrupole mass spectrometer (ICP-MS/MS) was compared with the conventional method using diode array detector (HPLC-DAD). Both methods were selective, but the chro
J. Braz. Chem. Soc.. Publicado em: 2020-02
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12. Thermal Infrared Enthalpimetry in Paper Microzone Plates for Green and High Throughput Determination of Wine Acidities
The use of paper devices in chemical analysis has been increased due to their low cost, high surface area, portability, and biodegradability. A novel use of paper devices is proposed using thermal infrared enthalpimetry (TIE) for a rapid, green, and high throughput determination of wine acidities. The determination of total, fixed, and volatile acidities in
J. Braz. Chem. Soc.. Publicado em: 2020-02