Thermal Diffusion of Weak Electrolytes III. The Soret Coefficients of Normal Carboxylic Acids

2000 ◽  
Vol 214 (1) ◽  
Author(s):  
L. Domonkos ◽  
J. Liszi
Keyword(s):  
Formic Acid ◽  
Aqueous Solutions ◽  
Carboxylic Acids ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Conductometric Method ◽  
New Model ◽  
Weak Electrolytes

A conductometric method is described and applied for the determination of the Soret coefficient of normal carboxylic acids in aqueous solutions in order to check a new model described in our previous papers. The Soret cell originally developed by Agar and Turner was applied with only minor modifications. The results show that the deviations between the measured and calculated Soret coefficients are lower than 2.5% except for formic acid (33% in average).

Thermal diffusion with hydrolysis in aqueous solutions of sodium carbonate

1991 ◽  
Vol 69 (10) ◽  
pp. 1584-1588 ◽  
Author(s):  
Hui Lü ◽  
Derek G. Leaist
Keyword(s):  
Steady State ◽  
Aqueous Solutions ◽  
Thermal Diffusion ◽  
Sodium Carbonate ◽  
Soret Coefficient ◽  
Mixed Electrolytes ◽  
Cold Plate ◽  
Aqueous Sodium ◽  
Aqueous Sodium Carbonate ◽  
Nonisothermal Conditions

A conductimetric technique is used to measure thermal diffusion in aqueous solutions of sodium carbonate. In dilute solutions hydrolysis produces significant amounts of sodium bicarbonate and sodium hydroxide: Na2CO3 + H2O = NaHCO3 + NaOH. The applied temperature gradient causes the various solutes to migrate to the cooler parts of the solution. NaOH is found to diffuse more rapidly than NaHCO3, leading to the accumulation of excess NaOH (relative to NaHCO3) at the cold plate. Binary Na2CO3(m) + H2O mixtures therefore separate into ternary Na2CO3(m1) + NaOH(m2) + H2O mixtures under nonisothermal conditions. The steady-state molality gradients dm1/dT and dm2/dT and the ternary heats of transport of aqueous Na2CO3 and NaOH are reported. Key words: aqueous sodium carbonate, hydrolysis, mixed electrolytes, Soret coefficient, thermal diffusion.

scholarly journals Spectrophotometric Determination of the CuSO4 Soret Coefficient of a CuSO4-H2O Binary Solutions System

2010 ◽  
Vol 1 (2) ◽  
pp. 73-76
Author(s):  
Ijang Rohman ◽  
Djaka Sasmita ◽  
Iip Izul Falah
Keyword(s):  
Thermal Diffusion ◽  
Spectrophotometric Determination ◽  
Soret Coefficient ◽  
Binary Solutions ◽  
Short Column ◽  
Metal Plates ◽  
Different Temperatures

A spectrophotometric technique for the determination of the CuSO4 soret coefficient of a CuSO4-water binary solutions system is described. A short column of solutions is placed between horizontal metal plates that are held at different temperatures. The subsequent changes in composition due to thermal diffusion are followed by monitoring changes of transmittance near the end of the solutions column. In water, CuSO4 diffuses to the warm compartment of column. The soret coefficient of CuSO4 0.0254 molal in water agrees with the appropriate theory, i.e. 17.60x10-3 °C-1 on the average.

Thermal diffusion of aqueous alcohols

1989 ◽  
Vol 67 (5) ◽  
pp. 867-870
Author(s):  
Ashis Kumar Mukherjee ◽  
S. K. Sanyal
Keyword(s):  
Aqueous Solutions ◽  
Temperature Coefficient ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Local Entropy ◽  
Solvent Interactions ◽  
Solvent Water ◽  
Heat Of Transport ◽  
Sintered Glass ◽  
Experimental Values

The thermal diffusion of aqueous solutions of methanol, ethanol, propan-1-ol, butan-1-ol, ethan-1,2-diol, andpropan-1,2-diol contained in the pores of a sintered glass disc (of porosity G4) has been studied. The Soret coefficient (σ) and the heat of transport [Formula: see text] values are reported in the temperature range of 25–40 °C. The heat capacities of transport are ascertained at 30 °C from the temperature coefficient of heat of transport values. The results are explained on the basis of changes in local entropy in the solvent (water), arising out of solute–solvent interactions. Correlations of the observed experimental values with certain relevant thermodynamic parameters, taken from the literature, have also been sought, with encouraging results. Keywords: thermal diffusion, heat of transport, entropy of hydration.

Determination of the soret coefficient in a thermal-diffusion column operating in the sampling mode

1977 ◽  
Vol 33 (5) ◽  
pp. 1359-1363 ◽  
Author(s):  
G. D. Rabinovich ◽  
M. A. Bukhtilova ◽  
V. P. Ivakhnik
Keyword(s):  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Diffusion Column

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.

LC–MS/MS Determination of Apigenin in Rat Plasma and Application to Pharmacokinetic Study

2020 ◽  
Vol 21 ◽  
Author(s):  
Shixing Zhu ◽  
Jiayuan Zhang ◽  
Zhihua Lv ◽  
Mingming Yu
Keyword(s):  
Formic Acid ◽  
Pharmacokinetic Study ◽  
Ammonium Acetate ◽  
Rat Plasma ◽  
Biological Properties ◽  
Plasma Samples ◽  
Supply Rate ◽  
Natural Plant ◽  
Ammonium Acetate Buffer

Background: Apigenin, a natural plant flavone, has been shown to possess a variety of biological properties. Objective: In this report, a highly selective and sensitive LC-MS/MS method was developed and validated for the determination of apigenin in rat plasma. Methods: Analysts were separated on the HSS T3 column (1.8 μm 2.1×100 mm) using acetonitrile and 0.1% formic acid in 2 mM ammonium acetate buffer at a supply rate of 0.200 mL/min as eluent in gradient model. Results: Plasma samples were treated by protein precipitation using acetonitrile for the recovery ranging from 86.5% to 90.1% for apigenin. The calibration curves followed linearity in the concentration range of 0.50-500 ng/mL. The inter-day and intra-day precisions at different QC levels within 13.1% and the accuracies ranged from -10.6% to 8.6%. Conclusion: The assay has been successfully applied to the pharmacokinetic study of apigenin in rats.

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