Probing NaCl hydrate formation from aqueous solutions by terahertz time-domain spectroscopy

2020 ◽  
Vol 22 (32) ◽  
pp. 17791-17797 ◽  
Author(s):  
Ligang Chen ◽  
Guanhua Ren ◽  
Liyuan Liu ◽  
Pan Guo ◽  
Endong Wang ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Time Domain ◽  
Hydrate Formation ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

The cooling-induced formation of a hydrate in aqueous NaCl solutions was probed using terahertz time-domain spectroscopy (THz-TDS).

scholarly journals Salt effects on the picosecond dynamics of lysozyme hydration water investigated by terahertz time-domain spectroscopy and an insight into the Hofmeister series for protein stability and solubility

2016 ◽  
Vol 18 (22) ◽  
pp. 15060-15069 ◽  
Author(s):  
Katsuyoshi Aoki ◽  
Kentaro Shiraki ◽  
Toshiaki Hattori
Keyword(s):  
Aqueous Solutions ◽  
Protein Stability ◽  
Time Domain ◽  
Protein Solubility ◽  
Hydration Water ◽  
Hofmeister Series ◽  
Terahertz Time Domain Spectroscopy ◽  
Salt Effects ◽  
Time Domain Spectroscopy ◽  
Insight Into

The addition of salts into protein aqueous solutions causes changes in protein solubility and stability, the ability of which is known to be ordered in the Hofmeister series.

Low-frequency dynamics of proteins and aqueous solutions studied by terahertz time-domain spectroscopy

2013 ◽  
Author(s):  
Naoki Yamamoto ◽  
Akané Ishihara ◽  
Azusa Kaneko ◽  
Haruka Iguchi ◽  
Ohki Kambara ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Time Domain ◽  
Low Frequency ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

scholarly journals Relationships between Molecular Structure of Carbohydrates and their Dynamic Hydration Shells Revealed by Terahertz Time-Domain Spectroscopy

2021 ◽  
Vol 22 (21) ◽  
pp. 11969
Author(s):  
Nikita V. Penkov
Keyword(s):  
Aqueous Solutions ◽  
Time Domain ◽  
Water Structure ◽  
Free Water ◽  
Equatorial Orientation ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Glycosidic Bonds ◽  
Hydration Shells ◽  
Hydrogen Bond Energies

Despite more than a century of research on the hydration of biomolecules, the hydration of carbohydrates is insufficiently studied. An approach to studying dynamic hydration shells of carbohydrates in aqueous solutions based on terahertz time-domain spectroscopy assay is developed in the current work. Monosaccharides (glucose, galactose, galacturonic acid) and polysaccharides (dextran, amylopectin, polygalacturonic acid) solutions were studied. The contribution of the dissolved carbohydrates was subtracted from the measured dielectric permittivities of aqueous solutions based on the corresponding effective medium models. The obtained dielectric permittivities of the water phase were used to calculate the parameters describing intermolecular relaxation and oscillatory processes in water. It is established that all of the analyzed carbohydrates lead to the increase of the binding degree of water. Hydration shells of monosaccharides are characterized by elevated numbers of hydrogen bonds and their mean energies compared to undisturbed water, as well as by elevated numbers and the lifetime of free water molecules. The axial orientation of the OH(4) group of sugar facilitates a wider distribution of hydrogen bond energies in hydration shells compared to equatorial orientation. The presence of the carboxylic group affects water structure significantly. The hydration of polysaccharides is less apparent than that of monosaccharides, and it depends on the type of glycosidic bonds.

A Study of the Effect of a Protein on the Structure of Water in Solution Using Terahertz Time-Domain Spectroscopy

2017 ◽  
Vol 72 (2) ◽  
pp. 257-267 ◽  
Author(s):  
Nikita Penkov ◽  
Valery Yashin ◽  
Eugeny Fesenko ◽  
Andrew Manokhin ◽  
Eugeny Fesenko
Keyword(s):  
Aqueous Solutions ◽  
Aqueous Phase ◽  
Time Domain ◽  
Relaxation Times ◽  
Free Water ◽  
Model Parameters ◽  
Biological Macromolecules ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Hydration Shells

Terahertz time-domain spectroscopy (THz-TDS) was used to determine the spectra (range = 1.2–120 cm−1) of aqueous solutions of bovine serum albumin (BSA) at pH range 2.5–10. Under each of the selected pH, BSA molecules exist in a different conformation, compared to other pH values. The spectra were used to calculate the functions of the dielectric permittivity of BSA solutions. Dielectric functions of the aqueous phase of BSA solutions were calculated based on the Bruggeman model, without the contribution of BSA itself. Fitting of the dielectric functions was performed using a model which includes three water spectral bands: two relaxation bands with relaxation times of about 8.28 and 0.3 ps and a vibrational band with a maximum of about 180 cm−1. The parameters of these bands were determined through fitting and physical interpretation at the molecular level can be provided for each of them. A comparison between the values of model parameters of solutions with BSA and without BSA allowed to conclude that the main effect of BSA is the formation of strongly bound hydration shells in the immediate proximity to the protein molecule. At the same time, the structure of more distant layers of the hydration shells is destroyed, with an increased formation of free water molecules. Some differences are observed in the effect of different BSA conformations on the aqueous phase of solution. The proposed approach can be generalized and applied for studying of a wide class of biological macromolecules in aqueous solutions.

scholarly journals Чувствительность отражательных терагерцовых сенсоров водных растворов

2021 ◽  
Vol 91 (2) ◽  
pp. 315
Author(s):  
А.Б. Сотский ◽  
М.М. Назаров ◽  
С.С. Михеев ◽  
Л.И. Сотская
Keyword(s):  
Aqueous Solutions ◽  
Silicon Wafer ◽  
Time Domain ◽  
Glucose Concentration ◽  
Dissipative Structure ◽  
Solution Structure ◽  
Dielectric Film ◽  
Terahertz Pulse ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

Sensitivity of sensors of the composition of aqueous solutions in which it is detected the terahertz pulse reflected from the dielectric film – solution structure is investigated. It is shown that the maximum of the sensitivity is achieved by choosing the angles of incidence and radiation frequencies, providing zero reflection of monochromatic radiation from the named dissipative structure. Conditions for the realization of such reflection for waves of s- and p-polarization are established. Calculations are confirmed experimentally for the sensor of glucose concentration in water, which uses a thin silicon wafer, separating solution from air. It is shown that with the use of the terahertz time-domain spectroscopy method the sensor of the proposed structure allows reliable to detect and distinguich glucose impurities of concentration 10 and 30 g / l.

Feasibility Study on Rapid Analysis of Doxycycline Hydrochloride Aqueous Solution by Terahertz Time-Domain Spectroscopy

2019 ◽  
Vol 62 (1) ◽  
pp. 205-212
Author(s):  
Yuxin Huang ◽  
Chen Wang ◽  
Jianyuan Qin ◽  
Wendao Xu ◽  
Min Chen ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Time Domain ◽  
Rapid Analysis ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Thz Spectroscopy ◽  
Terahertz Time Domain Spectroscopy ◽  
Transmission Method ◽  
Time Domain Spectroscopy ◽  
Terahertz Transmission

Abstract. Antibiotics have been extensively applied in the treatment of infections in food-producing animals. However, the residues of these agents create a potential risk to human health. Among the methods available for rapid detection of antibiotics, terahertz time-domain spectroscopy (THz-TDS) has emerged as a technique with unique advantages over other methods. In this study, we demonstrate that rapid analysis of doxycycline hydrochloride (DCH) aqueous solutions could be achieved with THz-TDS through transmission, attenuated total reflection (ATR), and reflection with minimum detectable concentrations of 5000, 10, and 80 mg L-1, respectively, indicating that the ATR and reflection methods are superior to the transmission method for low-concentration aqueous solutions. This study is an effort to promote the development of rapid analysis of antibiotic residues in an aqueous matrix using THz spectroscopy. Keywords: Attenuated total reflection, Doxycycline hydrochloride solution, Reflection, Terahertz, Transmission.

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