scholarly journals INVESTIGATION AND OPTIMIZATION OF COMPLEXATION OF COBALT IONS WITH DIHYDROQUERCETIN IN AQUEOUS SOLUTIONS

2019 ◽  
pp. 95-104
Author(s):  
Елена (Elena) Владимировна (Vladimirovna) Столповская (Stolpovskaya) ◽  
Наталья (Natal'ya) Николаевна (Nikolaevna) Трофимова (Trofimova) ◽  
Василий (Vasiliy) Анатольевич (Anatol'evich) Бабкин (Babkin) ◽  
Роман (Roman) Георгиевич (Georgievich) Житов (Zhitov)
Keyword(s):  
Aqueous Solutions ◽  
Bound Water ◽  
Analysis Data ◽  
Molar Ratio ◽  
Elemental Analysis Data ◽  
Cobalt Ions ◽  
Ph Values ◽  
Reaction Solution ◽  
Form Compound

We continue to study the reactions of complexation of biogenic metal ions with flavonoid dihydroquercetin (DHQ). The interaction of Co2+ ions with DHQ in aqueous solutions has been studied. It is established that complexes with different stoichiometry are formed at different pH values of the solution. Changing the pH of the solution from 6.0 to 7.0 leads to the formation of compounds 1–3 with a metal: flavonoid ligand (Met: L) ratio from 1: 2 at pH 6.0 (1) via 2: 3 at pH 6.4 -6.7 (2) to 1: 1 at pH 6.8-7.0 (3). Using the method of thermogravimetry with elemental analysis data, the most probable composition of compounds was established with the determination of the amount of bound water: [CoL2(H2O)4] for 1, [Co2L3(OH)(H2O)4] for 2 and [CoL(OH)(H2O)2] for 3. The conditions for the complexation of Co2+ ions with dihydroquercetin in aqueous solutions to form compound 2, optimized for the yield of the product, are proposed. pH of the solution is 6.7, the reaction time is 15 minutes, the temperature of the reaction solution is 90 °C, molar ratio of the initial reagents DHQ:Co2+ is 1: 1.5, initial concentrations are 0,020 M DHQ and 0,030 M Co2+, the source of Co2+ is CoSO4∙7H2O. The yield of the product is 81.8 %.

scholarly journals Modification of Pea Starch and Dextrin Polymers with Isocyanate Functional Groups

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 939 ◽  
Author(s):  
Reza Hosseinpourpia ◽  
Arantzazu Echart ◽  
Stergios Adamopoulos ◽  
Nagore Gabilondo ◽  
Arantxa Eceiza
Keyword(s):  
Moisture Sorption ◽  
Analysis Data ◽  
Water Vapor Sorption ◽  
Molar Ratio ◽  
Elemental Analysis Data ◽  
Slight Reduction ◽  
Modified Starch ◽  
13C Nuclear Magnetic Resonance ◽  
High Molar Ratio ◽  
Pea Starch

Pea starch and dextrin polymers were modified through the unequal reactivity of isocyanate groups in isophorone diisocyanate (IPDI) monomer. The presence of both urethane and isocyanate functionalities in starch and dextrin after modification were confirmed by Fourier transform infrared spectroscopy (FTIR) and 13C nuclear magnetic resonance (13C NMR). The degree of substitution (DS) was calculated using elemental analysis data and showed higher DS values in modified dextrin than modified starch. The onsets of thermal degradation and temperatures at maximum mass losses were improved after modification of both starch and dextrin polymers compared to unmodified ones. Glass transition temperatures (Tg) of modified starch and dextrin were lower than unmodified control ones, and this was more pronounced in modified dextrin at a high molar ratio. Dynamic water vapor sorption of starch and dextrin polymers indicated a slight reduction in moisture sorption of modified starch, but considerably lower moisture sorption in modified dextrin as compared to that of unmodified ones.

scholarly journals Development and Validation of Method for the Quantitative Determination of Zinc in its Chelate Complexes Using Energy Dispersive X-ray Fluorescence Spectroscopy

2021 ◽  
Vol 10 (4) ◽  
pp. 154-161
Author(s):  
А. V. Marukhlenko ◽  
Т. V. Maksimova ◽  
Т. V. Pleteneva ◽  
М. A. Morozova
Keyword(s):  
Fluorescence Spectroscopy ◽  
Aqueous Solutions ◽  
Quantitative Determination ◽  
Zinc Sulfate ◽  
Zinc Content ◽  
Chelate Complex ◽  
Molar Ratio ◽  
X Ray ◽  
Validation Parameters

Introduction. The production, standardization and quality control process of various dietary supplements containing chelated zinc requires validated quantitative assessment methods. In this work, we propose an X-ray fluorescence spectroscopy (XRF) technique for determining the zinc content in the composition of coordination compounds using the example of a synthesized chelate complex with methionine.Aim. To synthesize Zn(Met)2 chelate complex, to develop and validate a method for its quantitative analysis using the XRF method.Materials and methods. The synthesized zinc chelate complex was investigated by IR spectroscopy. The XRF method was used to develop a method for quantifying the zinc content in the synthesized complex. We used dry mixtures of zinc sulfate monohydrate and L-methionine (Met) in a molar ratio of Zn to Met – 1 : 1, 1 : 2, 1 : 4, 1 : 8 and 1 : 16 and also aqueous solutions of zinc sulfate and L-methionine in a molar ratio of Zn to Met 1 : 2 with Zn concentrations from 0.5 to 100 mmol/l as calibration standards. Complexometric titration was used as an arbitration method for the quantitative determination of zinc content in the samples under study.Results and discussion. The IR spectrum of chelate complex confirmed the presence of a donor-acceptor bond between Zn2+ and the nitrogen atom of amino group in methionine. The titration results showed chelate compounds have a composition corresponding to the stoichiometric formula Zn(Met)2. XRF analysis of dry standard mixed samples demonstrated the presence of matrix effect, that makes impossible an accurate assessment of zinc content in the chelate compound. According to the XRF spectra of aqueous solutions containing zinc sulfate and methionine in a ratio of 1 : 2 at a zinc concentration of 0.5; 1; 2; 3; 4; 5; 10; 25; 50 and 100 mmol/L, a calibration graph was constructed – the dependence of the fluorescence signal intensity for the Kα line of zinc on the concentration of zinc in the solution (r = 0.9996). The method was evaluated by the following validation parameters: specificity, linearity, correctness, precision, and analytical range. The specificity of the validated method was proven in the presence of copper, iron, and silver.Conclusion. The developed method make it possible to determine with sufficient precision and correctness the content of Zn2+ in its aqueous solutions of inorganic and organic nature by the XRF method in the concentration range from 3 to 100 mmol/l without the influence of the matrix.

Cadmium Removal by Flotation from Diluted Aqueous Solutions. Determination of the Optimum Separation Conditions

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Adrian Turtureanu
Keyword(s):  
Aqueous Solutions ◽  
Molar Ratio ◽  
Optimal Conditions ◽  
Air Flow Rate ◽  
Cadmium Removal ◽  
Initial Concentration ◽  
Dilute Aqueous Solutions ◽  
Very High ◽  
Optimum Separation

The paper presents the removal of cadmium by flotation from dilute aqueous solutions, at a laboratory scale, using an anionic collector (oleic acid). The optimum values of the main parameters influencing this process were determined: pH of Cd(II) solutions, molar ratio collector:Cd(II), air flow rate, flotation time and initial concentration of Cd(II). Using these optimal conditions, a very high removal degree of cadmium (over 99%) was obtained.

scholarly journals THE CRYOSCOPIC METHOD FOR THE DETERMINATION OF "BOUND WATER"

1934 ◽  
Vol 17 (3) ◽  
pp. 327-339 ◽  
Author(s):  
Ross Aiken Gortner ◽  
Willis Alway Gortner
Keyword(s):  
Aqueous Solutions ◽  
Environmental Conditions ◽  
Freezing Point ◽  
Physiological Responses ◽  
Bound Water ◽  
Gum Acacia ◽  
Preferential Adsorption ◽  
Sucrose Solutions ◽  
Water Values

1. The criticisms by Grollman (7) of the cryoscopic method for the determination of bound water as proposed by Newton and Gortner (1) have been considered, and it is pointed out that even admitting the correctness of his contentions does not negative the conclusion that bound water values as determined by the cryoscopic method parallel in a remarkable manner the physiological responses of plants to environmental conditions. 2. A new method of calculating the true freezing point of a solution is proposed. 3. Gum acacia in aqueous sucrose solutions shows positive amounts of bound water to the extent of 0.6 to 0.7 gm. of bound water per gram of gum. 4. Gum acacia in aqueous solutions of KCl and KBr shows slightly negative amounts of bound water, indicating a preferential adsorption of the solute rather than the solvent.

scholarly journals INVESTIGATION AND OPTIMIZATION OF COMPLEXATION OF MANGANESE (II) IONS WITH DIHY-DROQUERCETIN IN AQUEOUS SOLUTIONS

2020 ◽  
pp. 47-56
Author(s):  
Yelena Vladimirovna Stolpovskaya ◽  
Natalya Nikolaevna Trofimova ◽  
Vasily Anatolyevich Babkin ◽  
Spartak Spiridonovich Khutsishvili ◽  
Roman Georgievich Zhitov ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Maximum Yield ◽  
Bound Water ◽  
Fluorescence Analysis ◽  
Molar Ratio ◽  
Complexation Reaction ◽  
Stoichiometric Ratio ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Molar Ratios

The purpose of this work was to study and optimize the complexation reaction of Mn2+ ions with flavonoid dihydroquercetin (DHQ) in aqueous solutions. It was found that the interaction of DHQ (0.015–0.030 M) with manganese (II) salts at molar ratios of DHQ : Mn2+ from 1 : 1 to 1 : 3 at pH 6.9–7.9 leads to the formation of a complex compound (CC) with a stoichiometric ratio of metal : flavonoid ligand (Met : L) 1 : 1. The conditions for the complexation of Mn2+ ions with dihydroquercetin at laboratory conditions optimized for the yield of the product, are proposed. The maximum yield of the complex (95%) was achieved at the interaction of DHQ with Mn(CH3COO)2∙4H2O under conditions: pH 7.7, 70 °C, the reaction time was 15 min, the molar ratio of the initial reagents DHQ: Mn2+ was 1 : 1.5, the initial concentrations were 0.020 M DHQ and 0.030 M Mn2+. The most probable composition of the complex with the determination of the amount of bound water [MnL(OH)(H2O)2] and the structure of the complex were established using the data of thermogravimetry (TG), differential scanning calorimetry (DSC), elemental analysis and X-ray fluorescence analysis (XRF), confirmed by the data of total reflection X-ray fluorescence analysis (TXRF), and EPR spectroscopy data.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

Synthesis, Characterization and Thermal Degradation of Some New 3,5-dimethyl Pyrazole Derivatives

2017 ◽  
Vol 68 (2) ◽  
pp. 317-322
Author(s):  
Anca Mihaela Mocanu ◽  
Constantin Luca ◽  
Alina Costina Luca
Keyword(s):  
Thermal Degradation ◽  
Degradation Mechanism ◽  
New Products ◽  
Analysis Data ◽  
Biological Properties ◽  
Elemental Analysis Data ◽  
Ftir Analysis ◽  
Spectral Measurements ◽  
Chemical Structures ◽  
And Storage

The purpose of this research is to synthetize, characterize and thermal degradation of new heterolytic derivates with potential biological properties. The derivates synthesis was done by obtaining new molecules with pyralozone structure which combine two pharmacophore entities: the amidosulfonyl-R1,R2 phenoxyacetil with the 3,5-dimethyl pyrazole which can have potential biological properties. The synthesis stages of the new products are presented as well as the elemental analysis data and IR, 1H-NMR spectral measurements made for elucidating the chemical structures and thermostability study which makes evident the temperature range proper for their use and storage. The obtained results were indicative of a good correlation of the structure with the thermal stability as estimated by means of the initial degradation temperatures as well as with the degradation mechanism by means of the TG-FTIR analysis.

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