scholarly journals HEAT CAPACITY PROPERTIES OF AQUEOUS BUFFER SOLUTIONS OF L-HISTIDINE IN A WIDE TEMPERATURE RANGE

2019 ◽  
Vol 62 (11) ◽  
pp. 78-84
Author(s):  
Elena Yu. Tyunina ◽  
Anna A. Kuritsyna
Keyword(s):  
Heat Capacity ◽  
Amino Acid ◽  
Specific Heat ◽  
Sodium Phosphate ◽  
Heat Capacities ◽  
Buffer Solution ◽  
Partial Molar Heat Capacities ◽  
Aqueous Buffer ◽  
Temperature Range ◽  
Buffer Solutions

The influence of temperature and concentration of L-histidine on the heat capacity properties of its aqueous buffer solutions was studied by differential scanning calorimetry. The investigations were carried out in aqueous buffer solutions (pH 7.4) containing monobasic sodium phosphate and dibasic sodium phosphate, which brings the environment closer to the conditions of real biological systems. The pH values of the solutions were fixed with a digital pH meter Mettler Toledo, model Five-Easy (Switzerland). The differential scanning microcalorimeter SCAL-1 (Biopribor, Pushchino, Russia) was used for measure the specific heat capacity of the system under study. It was equipped with Peltier thermoelectric elements, two measuring glass cells with an internal volume of 0.377 cm3, as well as a computer terminal and software for calculating heat capacity. The standard error of measurement of the specific heat for the studied solutions was within ±7·10-3 J·K-1·g-1. The experimental values of the specific heat of solutions of the amino acid in a phosphate buffer solvent in the temperature range (283.15 – 343.15) K were obtained. The concentration of histidine was varied from (0.00215 to 0.03648) mol·kg-1. All the studied solutions were prepared by the gravimetric method using Sartorius-ME215S scales (with a weighing accuracy of 1·10-5 g). The apparent molar heat capacities of L-histidine in the buffer solution, as well as its partial molar heat capacities at infinite dilution, were determined. The calculated molar parameters increase with an increase in both temperature and amino acid concentration. It was shown that the partial molar heat capacities transfers of L-histidine from water to the buffer solution have positive values in the temperature range studied. The results are discussed on base of the Gurney model.

scholarly journals INTERACTION OF NICOTINIC ACID WITH L-PHENYLALANINE IN BUFFER SOLUTIONS: HEAT CAPACITY AND VOLUME PROPERTIES STUDY

2017 ◽  
Vol 60 (4) ◽  
pp. 33
Author(s):  
Elena Yu. Tyunina ◽  
Valentin G. Badelin ◽  
Valentina S. Egorkina
Keyword(s):  
Heat Capacity ◽  
Amino Acid ◽  
Complex Formation ◽  
Nicotinic Acid ◽  
Heat Capacities ◽  
Buffer Solution ◽  
Aqueous Buffer ◽  
Acid Buffer ◽  
Buffer Solutions ◽  
Volume Properties

Thermodynamic and physicochemical properties of multicomponent aqueous solutions containing biologically active solutes are important in various areas of applied chemistry and are essential for understanding the chemistry of biological systems. Interactions between nicotinic acid (NA) and L-phenylalanine (Phe) were studied in aqueous phosphate buffer solutions (pH=7.35) by differential scanning calorimetry and volume methods. Heat capacities and densities of nicotinic acid-buffer, L-phenylalanine-buffer, and nicotinic acid-L-phenylalanine-buffer mixtures were determined at T=(288.15, 298.15, 308.15 and 318.15) K using the microdifferential scanning calorimeter SCAL-1 (Pushchino, Russia) and the density meter DSA 5000 M (Anton Paar). The apparent molar heat capacities (fCp) and apparent molar volumes (Vφ,NA) of nicotinic acid in buffer solution and in buffer 0.0120 mol×kg-1 amino acid solutions were evaluated. The concentration of NA was varied from (0.0079 to 0.036) mol×kg-1. The first and second differentials values were determined for NA in an aqueous buffer solution and for NA in an aqueous amino acid buffer solution. The interaction of NA with Phe is accompanied by complex formation. NA molecules in an aqueous buffer solution are water structure breakers, then the structure breaking effects of NA decrease as a result of interactions with Phe molecules during the complex formation in an aqueous amino acid buffer solution. The results were discussed in terms of various interactions taking place in this system.Forcitation:Tyunina E.Yu., Badelin V.G., Egorkina V.S. Interaction of nicotinic acid with L-phenylalanine in buffer solutions: heat capacity and volume properties study. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 4. P. 33-39. 

scholarly journals Suitable model for the calculation of the correlation between the real and the average specific heat capacity and possibilities of its application

2013 ◽  
Vol 67 (3) ◽  
pp. 495-511
Author(s):  
Branko Pejovic ◽  
Ljubica Vasiljevic ◽  
Vladan Micic ◽  
Mitar Perusic
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Heat Capacities ◽  
Practical Significance ◽  
Suitable Model ◽  
The Real ◽  
Temperature Range ◽  
Specific Heat Capacities ◽  
Differential Properties

Starting from the definition of the average specific heat capacity for chosen temperature range, the analytic dependence between the real and the mean specific heat capacities is obtained using differential and integral calculation. The obtained relation in differential form for the defined temperature range allows for the problem to be solved directly, without any special restrictions on its use. Using the obtained relation, a general model in the form of a polynomial of arbitrary degree in the function of temperature was derived, which has more suitable and faster practical application and is more general in character than the existing model. New graphical method for solving the problem is obtained based on differential geometry and using the derived equation. This may also have practical significance since many problems in thermodynamics are solved analytically and graphically. This result was used in order to obtain the amount of specific heat exchanged using an analytical model or a planimetric method. In addition, this graphical solution was used for the construction of the diagram showing the dependence between the specific heat exchanged and temperature. This diagram also gives a simple graphical procedure for the calculation of the real and the average specific heat capacity for arbitrary temperature or temperature interval. The confirmation for all graphic constructions is obtained using the differential properties between thermodynamic units. In order for the graphical solutions presented to be applicable in practice, suitable ratio coefficients have been determined for all cases. Verification of the model presented, as well as the possibilities of its application, were given using several characteristic examples of semi-ideal and real gas. Apart from linear and non-linear functions in the form of polynomials, the exponential function of the dependence between specific heat capacities and temperature was also analysed in this process.

“TEMPERATURE” FLUCTUATION AND HEAT CAPACITIES OF QUARKS AND π MESON

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1912-1916
Author(s):  
X. H. SHI ◽  
G. L. MA ◽  
Y. G. MA ◽  
X. Z. CAI ◽  
J. H. CHEN
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Impact Parameter ◽  
Specific Heat Capacity ◽  
Temperature Fluctuation ◽  
Temperature Fluctuations ◽  
Heat Capacities ◽  
Transverse Mass ◽  
Parton Cascade ◽  
Specific Heat Capacities

Specific heat capacities of π meson and different quarks after parton cascade AMPT model in Au + Au collisions at [Formula: see text] have been tentatively extracted from the event-by-event temperature fluctuations in the region of low transverse mass. The specific heat capacity of π meson shows a slight dropping trend with increasing impact parameter. The specific heat capacities of different quarks increase with the mass of quark, and the sum of up and down quark's specific heat capacities was found to be approximately equal to that of π meson.

Specific Heat Capacity Estimations for Biologically and Medicinally Important Compounds: Lidocaine Hydrochloride, Clove Oil and Piperine using DSC Technique

2020 ◽  
Vol 10 ◽  
Author(s):  
Gaurav Gupta ◽  
Vasim Shaikh ◽  
Sachin Kalas ◽  
Kesharsingh Patil
Keyword(s):  
Heat Capacity ◽  
Ionic Liquid ◽  
Heat Flow ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Chemical Potential ◽  
Lidocaine Hydrochloride ◽  
Clove Oil ◽  
Temperature Range ◽  
Thermal Gravimetry

Aims: To study the specific heat capacity for biologically and medicinally important compounds, namely, lidocaine hydrochloride, clove oil and brta-Piperine using DSC technique. Background: One of the main problems in the science of medicine is the application of drug molecules with limited solubility in water and in biofluids. Solubility is related to chemical potential of the solutes involved which imparts free energy avenues, a necessary requirement for equilibrium processes. The convincing solutions for solving this issue are the utilization of ionic liquids as drug. Lidocaine is the most widely utilized intraoral injected dental anesthetic prior to performing painful medical procedures. Besides that, lidocaine hydrochloride is a salt which is having melting point 76 0C (349 K) and behaves as ionic liquid after melting. Clove oil and β-piperine are very well-known naturally occurring medicinal compounds having broad spectrum of applications. Objective: To study the thermal gravimetry analysis behaviour for lidocaine hydrochloride, clove oil and β-piperine. To compute specific heat capacity at constant pressure, as a function of temperature for the studied systems. Method: In the present communication, the studies of thermal gravimetry analysis (TGA) and differential scanning calorimetry (DSC) for these compounds are described. The data of heat flow have been utilized to obtain specific heat capacity (Cp) values for lidocaine hydrochloride, clove oil and β-piperine over a temperature range in between 75 0C (348 K) and 155 0C (428 K) based upon the methodology we have developed. Result: The data of heat flow have been utilized to obtain specific heat capacity (Cp) values for lidocaine hydrochloride, clove oil and β-piperine over a temperature range in between 75 0C (348 K) and 155 0C (428 K) based upon the methodology we have developed. Conclusion: LC•HCl behaves as an ionic liquid between 76 and 230 0C (349 and 503 K). Clove oil is having lower specific heat capacity values and is similar to other organic aromatic compounds while piperine exhibits comparative high specific heat capacity values indicating possibilities of intramolecular hydrogen bonding which is generally not affected by temperature.

Estimation of the heat capacity of CdTe semiconductor

2016 ◽  
Vol 30 (04) ◽  
pp. 1650026 ◽  
Author(s):  
Hüseyin Koç ◽  
Erhan Eser
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Binomial Coefficient ◽  
Debye Model ◽  
The Other ◽  
Temperature Range ◽  
Theoretical Results ◽  
Good Agreement

The aim of this paper is to provide a simple and reliable analytical expression for the thermodynamic properties calculated in terms of the Debye model using the binomial coefficient, and examine specific heat capacity of CdTe in the 300–1400 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. The calculated results are in good agreement with the other results over the entire temperature range.

Thermodynamic Properties of Ionized Gases at High Temperatures

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Kian Eisazadeh-Far ◽  
Hameed Metghalchi ◽  
James C. Keck
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
High Temperatures ◽  
Mole Fraction ◽  
Specific Heat Capacity ◽  
Local Equilibrium ◽  
Equilibrium Conditions ◽  
New Model ◽  
Temperature Range

Thermodynamic properties of ionized gases at high temperatures have been calculated by a new model based on local equilibrium conditions. Calculations have been done for nitrogen, oxygen, air, argon, and helium. The temperature range is 300–100,000 K. Thermodynamic properties include specific heat capacity, density, mole fraction of particles, and enthalpy. The model has been developed using statistical thermodynamics methods. Results have been compared with other researchers and the agreement is good.

SPECIFIC HEATS AND LATENT HEAT OF FUSION OF ICE

1930 ◽  
Vol 3 (3) ◽  
pp. 205-213 ◽  
Author(s):  
W. H. Barnes ◽  
O. Maass
Keyword(s):  
Heat Capacity ◽  
Latent Heat ◽  
Adiabatic Calorimeter ◽  
Heat Capacities ◽  
Heat Of Fusion ◽  
Final Temperature ◽  
Latent Heat Of Fusion ◽  
Temperature Range ◽  
Specific Heats

Values for the heat capacities of ice and resulting water from initial temperatures of between 0 °C. and − 78.5 °C. to a final temperature of + 25.00 °C. are measured to ± 0.05% or better with an improved adiabatic calorimeter previously described. The specific heats of ice over the temperature range 0° C. to − 80 °C. are found and the latent heat of fusion of ice at 0 °C. is obtained from these heat capacity determinations.

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