Thermophysical Properties of Aqueous Solution of Ammonium-Based Ionic Liquids

Umapathi, Reddicherla; Attri, Pankaj; Venkatesu, Pannuru

doi:10.1021/jp502400z

Cited by 64 publications

(80 citation statements)

References 55 publications

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“…The observed interactions between the protic IL and the non-associating propylene carbonate were attributed to changes in structure that resulted in labile protons establishing hydrogen bonding interactions with the carbonyl group of the solvent [41]. Similarly, Venkatesu and co-workers measured the density and viscosity of several short chain ammonium acetate and ammonium sulfate ILs using water as the cosolvent [48]. They noted negative deviations from ideal behavior for the volumetric data and also for the isentropic compressibility with increasing amounts of IL, but positive deviations for viscosity data.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Density, viscosity and excess properties in the trihexyltetradecylphosphonium chloride ionic liquid/methanol cosolvent system

McAtee

Heitz

2016

The Journal of Chemical Thermodynamics

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Section: Introductionmentioning

confidence: 99%

“…Anion effect was prominent with the sulfate derivatives showing a stronger association with water compared to the acetate ILs. The explanation is twofold: first, increased basicity results in stronger hydrogen bonding with water molecules; and second, stronger intermolecular interactions lead to a more compact structure [48].…”

Section: Introductionmentioning

confidence: 99%

Density, viscosity and excess properties in the trihexyltetradecylphosphonium chloride ionic liquid/methanol cosolvent system

McAtee

Heitz

2016

The Journal of Chemical Thermodynamics

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“…41 The cation and anion of an IL can for ion pair via hydrogen bonding, and some (including ammonium-based ILs such as TMAA) can H-bond with water as well, leading to altered viscosities and acidities. [41][42][43][44] These differences in properties might alter the droplets' composition during the electrospray mechanism, leading to changes in the neutralization of phosphates.…”

Section: The Exchangeable Sites Are Located On the Nucleobasesmentioning

confidence: 99%

Native Hydrogen/Deuterium Exchange Mass Spectrometry of Structured DNA Oligonucleotides

Largy

Gabelica

2019

Preprint

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Although hydrogen-deuterium exchange mass spectrometry (HDX/MS) is well-established for the analysis of the structure and dynamics of proteins, it is currently not exploited for nucleic acids. Here we used DNA G-quadruplex structures as model systems to demonstrate that DNA oligonucleotides are amenable to in-solution HDX/MS in native conditions. In trimethylammonium acetate solutions and in soft source conditions, the protonated phosphate groups are fully backexchanged in the source, while the exchanged nucleobases remain labeled without detectable gas-phase back-exchange. As a result, the exchange rates depend strongly on the secondary structure (hydrogen bonding status) of the oligonucleotides, but neither on their charge state nor on the presence of non-specific adducts. We show that native mass spectrometry methods can measure these exchange rates on the second to the day time scale with high precision. Such combination of HDX with native MS opens promising avenues for the analysis of the structural and biophysical properties of oligonucleotides and their complexes.In-solution HDX/MS is increasingly used to study the structural dynamics and interactions of proteins, in particular since the advent of automated systems. It relies on measuring exchange rates of backbone amide hydrogens in a deuterium-rich buffer, because these rates are heavily dependent on hydrogen-bonding and solvent accessibility. [1][2][3][4][5][6][7][8][9] Since all amino-acid (except prolines) possess an amide hydrogen, HDX/MS can effectively cover the entire sequence. HDX/MS is particularly valuable for proteins that are not amenable to X-Ray diffraction or NMR experiments, because of e.g. their large size, high dynamics, or limited availability. In this manuscript, we show that HDX/MS is also particularly well suited to study structured oligonucleotides ( Figure 1).Oligonucleotides contain several exchangeable sites: the 5'-and 3'-OH termini, the 2'-OH of RNA riboses (not explored herein), the phosphates, and the amino and imino hydrogens of bases. The -OH termini obviously do not cover the whole sequence, and are not good markers of the structure. The phosphate groups do cover the full sequence, but given their very low pKa (~ 1), all phosphate groups are fully deprotonated at physiological pH. 10 Some are neutralized during the electrospray process, but that may not provide a clear information on the oligonucleotide's structure and dynamics in the bulk solution.The nucleobases are involved in secondary structure formation via hydrogen bonds ( Figure 1A), and given that each base contains at least one exchangeable site (dG: 3, dA and dC: 2, dT: 1), they theoretically suffice to cover the whole sequence.Hydrogen exchange of nucleic acids with deuterium or tritium was in fact studied early on. Some of the earliest attempts at characterizing dsDNA breathing fluctuation on the minute time scale were made in the 1960s by H-T exchange quantified by scintillation counting. [11][12][13] The exchange was however too fast to resolve the surface ...

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“…The refractive index of the products of the enzymatic reactions, i.e., ammonium ions and bicarbonate ions is less than the effective refractive index of the ZnO layer over which Ur enzyme is immobilized (around 2.21). 19,28,29 Thus, the effective refractive index of the sensing media decreases due to the reaction between Ur enzyme and analyte urea. Now, as the concentration of urea solution increases in the sample cell, there is a consequent decrease in the refractive index of the sensing medium leading to a continuous decrease in the resonance angle with an increase in the concentration of the analyte (urea).…”

Section: Response Characteristics Of Urea Biosensor Using Surface Plamentioning

confidence: 99%

Table top surface plasmon resonance measurement system for efficient urea biosensing using ZnO thin film matrix

2016

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The present report addresses the application of surface plasmon resonance (SPR) phenomenon for urea sensing. The former promises a high sensitivity, label-free detection, and real-time information by monitoring the refractive index change at the metal–dielectric interface. In the present report, a highly sensitive urea biosensor has been developed by integrating a ZnO thin film matrix with the SPR technique. Kretschmann configuration has been used to excite the surface plasmon (SP) modes at the ZnO–metal (gold) interface using an indigeneously developed table top SPR measurement setup. Urease (Urs), the urea-specific enzyme, has been immobilized on the surface of ZnO thin film by physical adsorption technique. The SPR reflectance curves were recorded for the prism/Au/ZnO/Urs system in angular interrogation mode with phosphate-buffered saline (PBS) solution as the liquid media. The SPR resonance angle is found to be shifted toward a lower angle from 49.1 to 42.0 deg with an increase in the urea concentration (0 to 300 mg/dl) in the PBS solution. The developed sensor (prism/Au/ZnO/Urs) is found to be highly sensitive [sensitivity=0.039 deg/(mg/dl) or 203 deg/RIU] with detection accuracy of 0.045(deg)(−1).

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Thermophysical Properties of Aqueous Solution of Ammonium-Based Ionic Liquids

Cited by 64 publications

References 55 publications

Density, viscosity and excess properties in the trihexyltetradecylphosphonium chloride ionic liquid/methanol cosolvent system

Density, viscosity and excess properties in the trihexyltetradecylphosphonium chloride ionic liquid/methanol cosolvent system

Native Hydrogen/Deuterium Exchange Mass Spectrometry of Structured DNA Oligonucleotides

Table top surface plasmon resonance measurement system for efficient urea biosensing using ZnO thin film matrix

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