Determination of total concentration and bioaccessible fraction of metals in tomatoes and their derivatives by MIP OES

2021 ◽  
Vol 96 ◽  
pp. 103716
Author(s):  
Daisa Hakbart Bonemann ◽  
Ana Cláudia Beduhn Luckow ◽  
Camila Corrêa Pereira ◽  
Alexander Ossanes de Souza ◽  
Solange Cadore ◽  
...  
Keyword(s):  
Total Concentration ◽  
Mip Oes ◽  
Bioaccessible Fraction

scholarly journals AVALIAÇÃO DA CONCENTRAÇÃO TOTAL E DA FRAÇÃO BIOACESSÍVEL DE METAIS EM AMOSTRAS DE CASCA DE UVA DE CULTIVARES TANNAT E CABERNET SAUVIGNON POR MIP OES

Química Nova ◽  
2021 ◽  
Author(s):  
Bruno Jacobs ◽  
Daisa Bonemann ◽  
Camila Pereira ◽  
Alexander Souza ◽  
Ana Luckow ◽  
...  
Keyword(s):  
Total Concentration ◽  
Comparative Method ◽  
Total Content ◽  
Cabernet Sauvignon ◽  
Acid Decomposition ◽  
Grape Skins ◽  
Mip Oes ◽  
Bioaccessible Fraction

EVALUATION OF THE TOTAL CONCENTRATION AND THE BIOACCESSIBLE FRACTION OF METALS IN SAMPLES OF GRAPE SKINS OF CULTIVARS TANNAT AND CABERNET SAUVIGNON BY MIP OES. This paper describes the evaluation of the total concentration of Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Mn, Pb e Zn and the bioaccessible fraction of Ba, Cu, Fe, Mn, Pb and Zn in samples of grape skins from different cultivars (Vitis Viníferas Tannat and Cabernet Sauvignon) by MIP OES. For the determination of total concentration, acid decomposition with a reflux system adapted to the digestion tubes in the oxidizing medium of HNO3 and H2O2 were used. The accuracy of the method was verified by recovery tests, whose values ranged from 80 to 120%, as well as through a comparative method in closed system. Bi, Cd and Cr showed values for total content below the LOD or below the values acceptable for health while Pb is higher than 0.2 mg kg-1, for both cultivars. To evaluate the bioacessible fraction, the gastrointestinal system was simulated using an in vitro procedure, and its performance was assessed considering the bioaccessible fraction (supernatant) and the non-bioaccessible fraction, whose sum should be closed to the total concentration, and the results obtained were between 81 and 120%. Both cultivars showed similar values for the bioaccessible fractions (~13.5 – 53% of the total content).

Determination of total concentration and bioaccessible fraction of metals in infant cereals by MIP OES

2019 ◽  
Vol 77 ◽  
pp. 60-65 ◽  
Author(s):  
Alexander Ossanes de Souza ◽  
Camila Corrêa Pereira ◽  
Adriana Iven Heling ◽  
Eliézer Quadro Oreste ◽  
Solange Cadore ◽  
...  
Keyword(s):  
Total Concentration ◽  
Mip Oes ◽  
Bioaccessible Fraction

scholarly journals Mechanism of tubulin–colchicine recognition: a kinetic study of the binding of the colchicine analogues colchicide and isocolchicine

1997 ◽  
Vol 327 (3) ◽  
pp. 685-688 ◽  
Author(s):  
Chantal DUMORTIER ◽  
Qunying YAN ◽  
Susan BANE ◽  
Yves ENGELBORGHS
Keyword(s):  
Rate Constant ◽  
Total Concentration ◽  
Carbonyl Oxygen ◽  
Protein Fluorescence ◽  
Kinetic And Thermodynamic Parameters ◽  
Methoxy Groups ◽  
Displacement Experiments ◽  
Absorbance Changes ◽  
Initial Binding

Colchicide (IDE) is a colchicine (COL) analogue in which the C-10 methoxy group is replaced by a hydrogen atom. Its binding to tubulin is accompanied by a quenching of the protein fluorescence. The fluorescence decrease shows a monoexponential time dependence. The observed rate constant increases in a non-linear way with the total concentration of IDE, allowing the determination of a binding constant for an initial binding site (K1 = 5300±300 M-1) and the rate constant for the subsequent isomerization (k2 = 0.071±0.002 s-1) at 25 °C. The rate constant, k-2, for the reversed isomerization can be determined by displacement experiments. Despite the minor alteration of the C-ring substituent, the kinetic and thermodynamic parameters of binding are substantially different from those of COL itself, for both steps. In isocolchicine (ISO) the carbonyl oxygen atom and the methoxy groups of the C-ring have been interchanged. Its binding to tubulin only results in small fluorescence and absorbance changes. Therefore competition experiments with MTC [2-methoxy-5-(2ʹ,3ʹ,4ʹ-trimethoxyphenyl)-2,4,6-cycloheptatrien-1-one] were performed. ISO competes rapidly and with low affinity with MTC. Fluorimetric titrations of tubulin with MDL (MDL 27048 or trans-1-(2,5 dimethoxyphenyl)-3-[4-(dimethylamino)phenyl]-2-methyl-2-propen-1-one) in the presence and absence of ISO give evidence for the existence of a second, slow-reacting low-affinity site for ISO that is not accessible to MTC or MDL. The relevance of these results for the recognition of COL is analysed.

Application of Mixture Design and Kohonen Neural Network for Determination of Macro- and Microelement in Mullet (Mugil cephalus) by MIP OES

2021 ◽  
Author(s):  
Clissiane Soares Viana Pacheco ◽  
Floriatan Santos Costa ◽  
Wesley Nascimento Guedes ◽  
Marina Santos de Jesus ◽  
Thiago Pereira das Chagas ◽  
...  
Keyword(s):  
Neural Network ◽  
Mixture Design ◽  
Mugil Cephalus ◽  
Kohonen Neural Network ◽  
Mip Oes

Zur Untersuchung von Gleichgewichten instabiler Komplexe und die Bestimmung der Beweglichkeiten der einzelnen Spezies mittels Gegenstrom-Ionenwanderung / Investigation of the Equilibrium of Unstable Complexes and the Determination of their Mobility by Means of Countercurrent Ion Migration

1973 ◽  
Vol 28 (7) ◽  
pp. 1226-1227 ◽  
Author(s):  
B. A. Bilal
Keyword(s):  
Metal Cation ◽  
Total Concentration ◽  
Migration Process ◽  
Stationary Distributions ◽  
Ion Migration ◽  
Constant Distribution

In a countercurrent ion migration process the ion of an element (e. g. a metal cation) can form various unstable complexes with the anion of the countercurrent electrolyte. The total concentration of such an element in its stationary and locally constant distribution in a countercurrent ion migration column is then determined by the average mobility of all equilibrated species containing this element. From stationary distributions in their dependence on concentration the mobilities of the various species can be determined if the constants of the different equilibrium stages are known and vice versa.

scholarly journals Determination of Surfactants in Environmental Samples. Part II. Anionic Compounds

2013 ◽  
Vol 20 (2) ◽  
pp. 331-342 ◽  
Author(s):  
Ewa Olkowska ◽  
Marek Ruman ◽  
Anna Kowalska ◽  
Żaneta Polkowska
Keyword(s):  
Environmental Samples ◽  
Anionic Surfactants ◽  
Solid Phase ◽  
Total Concentration ◽  
Polar Group ◽  
Surface Active Agents ◽  
Assisted Extraction ◽  
Surface Active ◽  
Living Organisms

Abstract Surface active agents (SAA) with negative charge of polar group are named as anionic compounds. They are the main constituent of most products containing synthetic surfactants. The linear alkylbenzene sulfonates (LAS), alkyl ethoxysulfates (AES) and alkyl sulfates (AS) are typically applied from this class of compounds. Those surfactants are ingredients of household detergents and cleaners, laundry detergents, cosmetic etc. Moreover they can be applied in the paper, textile and tanning industry as optical brighteners, dispersant, wetting and suspending agents. They can be substrates in the formulation of different products like dyes, pigments, pesticides, exchange resins, plasticizers and pharmaceuticals. Anionic surfactants after use are passed into sewage-treatment plants, where they are partially degraded and adsorbed to sewage sludge (applied in agriculture fields). Finally, the anionic SAA or their degradation products are discharged into surface waters and onto bottom sediments, soils or living organisms. Therefore, it is important (widely application, bioaccumulation, toxicity for living organisms) to investigate the environmental fate of those class of compounds in more details. This research involves determination the concentration of anionic surfactants with use appropriated analytical techniques in environmental samples The official methodology for determination of anionic SAA in liquid samples is based on the ion-pair reaction of these analytes compounds with methylene blue (MB) and an extraction with toxic solvent chloroform. During isolation step of anionic compounds from solid samples are employed Soxhlet and ultrasonic-assisted extraction techniques with use of methanol or mixture of other organic solvents as extraction medium. To overcome disadvantages of those traditional techniques were applied following techniques at sample preparation step from liquid and solid matrices: solid-phase extraction (SPE) and solid-phases microextraction (SPME); accelerated solvent extraction (ASE), microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), respectively. For estimate total concentration of anionic analytes in extracts the spectrophotometric technique is used (as official regulation). For determination concentration of individual analytes were applied gas (derivatization step requires) and liquid chromatography mainly with mass spectrometry technique. The presence of anionic surface active agents was confirmed in various ecosystems (liquid and solid environmental samples).

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