Toward Understanding Solute–Solvent Interaction in Room-Temperature Mono- and Dicationic Ionic Liquids: A Combined Fluorescence Spectroscopy and Mass Spectrometry Analysis

2014 ◽  
Vol 118 (7) ◽  
pp. 1907-1915 ◽  
Author(s):  
Prabhat Kumar Sahu ◽  
Sudhir Kumar Das ◽  
Moloy Sarkar
Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 69 ◽  
Author(s):  
Shouhei Kawada ◽  
Seiya Watanabe ◽  
Shinya Sasaki ◽  
Masaaki Miyatake

The friction coefficients of ionic liquids were evaluated by many investigations. Most investigations used fluorine-based ionic liquids as lubricants. However, these ionic liquids produce the corrosion wear. This investigation focuses on the use of cyano-based ionic liquids as lubricants. Compared to fluorine-based ionic liquids, cyano-based ionic liquids exhibit high friction coefficients against steel material. This work examines how the friction coefficients of cyano-based ionic liquids are influenced by the type of sliding material used (AISI 52100, TiO2, and tetrahedral amorphous carbon). TiO2 lubricated with 1-ethyl-3-methylimidazolium tricyanomethanide, and ta-C lubricated with 1-butyl-1methylpyrrolidinium tetracyanoborate exhibited very low friction coefficients, smaller than fluorine-based ionic liquids. Time-of-Flight Secondary Ion Mass Spectrometry analysis showed that anions adsorb onto the worn surface, suggesting that anion adsorption is a critical parameter influencing friction coefficients. Quadrupole Mass Spectrometry measurements revealed that cations decompose on the nascent surface, preventing adsorption on the worn surface. These results suggest that low friction coefficients require the decomposition of cations and adsorption of anions. The reactivity of nascent surface changes with the sliding material used due to varying catalytic activity of the nascent surfaces.


2014 ◽  
Vol 92 (7) ◽  
pp. 611-615 ◽  
Author(s):  
Yafei Zhou ◽  
Junfeng Zhan ◽  
Xiang Gao ◽  
Cao Li ◽  
Konstantin Chingin ◽  
...  

Ionic liquids, known as green solvents, are of sustainable interest in modern chemistry, industry, and many other fields. Here, extractive electrospray ionization has been applied to transfer various room temperature ionic liquids into the gas phase for mass spectrometry analysis. Generated mass spectra display free cations (C+), anions (A–), and small salt clusters, such as C2A+ and CA2–, from strongly diluted ionic liquid samples (<10−8 mol/L) with high sensitivity and tolerance to chemical contamination. The eight ionic liquids based on the 1-butyl-3-methylimidazolium cation with different anions (OH–, HSO4–, Cl–, BF4–, AlCl4–, NO3–, Ac–, and PF6–) are investigated in the present work. Interestingly, the 1-butyl-3-methylimidazolium cation signal intensity is inversely correlated with the hydrogen bonding strength between the anion and cation. Our study indicates that the direct extractive electrospray ionization mass spectrometry analysis is a convenient method to screen ionic liquid libraries with regard to chemical composition, physicochemical properties, and supramolecular organization of ionic liquids.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Kanamoto ◽  
Takashi Tachibana ◽  
Yasushi Kitaoka ◽  
Toshio Hisatomi ◽  
Yasuhiro Ikeda ◽  
...  

Purpose. To investigate the effect of ocular hypertension-induced isomerization of aspartic acid in retinal proteins. Methods. Adult Wistar rats with ocular hypertension were used as an experimental model. D-β-aspartic acid-containing proteins were isolated by SDS-PAGE and western blot with an anti-D-β-aspartic acid antibody and identified by liquid chromatography-mass spectrometry analysis. The concentration of ATP was measured by ELISA. Results. D-β-aspartic acid was expressed in a protein band at around 44.5 kDa at much higher quantities in the retinas of rats with ocular hypertension than in those of normotensive rats. The 44.5 kDa protein band was mainly composed of α-enolase, S-arrestin, and ATP synthase subunits α and β, in both the ocular hypertensive and normotensive retinas. Moreover, increasing intraocular pressure was correlated with increasing ATP concentrations in the retinas of rats. Conclusion. Ocular hypertension affected the expression of proteins containing D-β-aspartic acid, including ATP synthase subunits, and up-regulation of ATP in the retinas of rats.


Sign in / Sign up

Export Citation Format

Share Document