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

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.

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

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20196211.6082 ◽

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.

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Study on the Interaction of Nicotinic Acid with l-Phenylalanine in Buffer Solution by Heat Capacity Measurements at Various Temperatures

Journal of Solution Chemistry ◽

10.1007/s10953-017-0570-6 ◽

2017 ◽

Vol 46 (2) ◽

pp. 249-258 ◽

Cited By ~ 6

Author(s):

E. Yu. Tyunina ◽

V. G. Badelin ◽

I. N. Mezhevoi

Keyword(s):

Heat Capacity ◽

Nicotinic Acid ◽

Buffer Solution ◽

Heat Capacity Measurements

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Thermodynamic characteristics of molecular interactions between L-tryptophan and nicotinic acid and uracyl in aqueous buffer solutions at 298 K

Russian Journal of Physical Chemistry A ◽

10.1134/s0036024415120031 ◽

2015 ◽

Vol 89 (12) ◽

pp. 2229-2233 ◽

Cited By ~ 7

Author(s):

V. G. Badelin ◽

E. Yu. Tyunina ◽

I. N. Mezhevoi ◽

G. N. Tarasova

Keyword(s):

Nicotinic Acid ◽

Molecular Interactions ◽

Thermodynamic Characteristics ◽

Aqueous Buffer ◽

Buffer Solutions

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ANALISIS MISKONSEPSI PADA MATERI LARUTAN PENYANGGA SISWA KELAS XI IPA MA SWASTA DARUL ULUM KUBU RAYA

AR-RAZI Jurnal Ilmiah ◽

10.29406/ar-r.v6i2.1219 ◽

2018 ◽

Vol 6 (2) ◽

Author(s):

Abdul Chozim

Keyword(s):

Diagnostic Test ◽

Multiple Choice ◽

Thinking Skills ◽

Buffer Solution ◽

Acid Buffer ◽

Buffer Solutions ◽

Common Misconception ◽

Test Instrument ◽

School Text ◽

Descriptive Method

The problems faced by the students in chemistry class, especially in Buffer Solutions, often caused a misunderstanding. Continuous misunderstanding can lead to a misconception. This study aimed to analyze the misconceptions in Buffer Solutions among the eleventh grade students of MA Darul Ulum Kubu Raya 2016/2017 using a Diagnostic Test instrument. Using a descriptive method, the data revealed collected by employing 10 items of multiple choice with their reasons. The study revealed that the misconceptions in Buffer Solutions occurred in all concepts. The most common misconception took place in the indicator of explaining how the base buffer solution works when it is added by a small amount of alkaline (80%). The lowest happened on the indicator of determining the mixture of compoundsof the acid buffer solution (31%). The misconception that occured in each indicator was 70.4%. The misconception was caused by the students’ associative thinking skills was 48.4%. Therefore, the factors related to misconceptions faced by the students in Buffer Solutions are the lack of understanding, the learning methods applied by the teacher, and the reference books, particularly the non-school text books.

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Thermodynamic characteristics of the interaction between nicotinic acid and phenylalanine in an aqueous buffer solution at 298 K

Russian Journal of Physical Chemistry A ◽

10.1134/s0036024413070078 ◽

2013 ◽

Vol 87 (8) ◽

pp. 1306-1309 ◽

Cited By ~ 8

Author(s):

V. G. Badelin ◽

E. Yu. Tyunina ◽

I. N. Mezhevoi ◽

G. N. Tarasova

Keyword(s):

Nicotinic Acid ◽

Thermodynamic Characteristics ◽

Buffer Solution ◽

Aqueous Buffer ◽

Aqueous Buffer Solution

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Thermodynamic Properties of L-Methionine and Nicotinic Acid in an Aqueous Buffer Solution

Russian Journal of Physical Chemistry A ◽

10.1134/s003602442011031x ◽

2020 ◽

Vol 94 (11) ◽

pp. 2238-2243

Author(s):

E. Yu. Tyunina ◽

V. I. Smirnov ◽

G. N. Tarasova

Keyword(s):

Thermodynamic Properties ◽

Nicotinic Acid ◽

Buffer Solution ◽

Aqueous Buffer ◽

Aqueous Buffer Solution

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Observation of complex formation between l-histidine and heterocyclic compounds in water and aqueous buffer solution using calorimetric and spectroscopic methods

Journal of Molecular Liquids ◽

10.1016/j.molliq.2019.01.092 ◽

2019 ◽

Vol 278 ◽

pp. 505-511 ◽

Cited By ~ 2

Author(s):

Elena Yu Tyunina ◽

Valentin G. Badelin ◽

Igor N. Mezhevoi

Keyword(s):

Complex Formation ◽

Heterocyclic Compounds ◽

Spectroscopic Methods ◽

Buffer Solution ◽

Aqueous Buffer ◽

Aqueous Buffer Solution

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Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19883072 ◽

1988 ◽

Vol 53 (12) ◽

pp. 3072-3079

Author(s):

Mojmír Skokánek ◽

Ivo Sláma

Keyword(s):

Heat Capacity ◽

Phase Transformation ◽

Phase Transformations ◽

Dimethyl Sulfoxide ◽

Liquidus Temperature ◽

Molar Heat Capacity ◽

Solid Phase ◽

Zinc Nitrate ◽

Heat Capacities ◽

Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

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