Mathematical Representation of Viscosity of Ionic Liquid + Molecular Solvent Mixtures at Various Temperatures Using the Jouyban-Acree Model

Article on mathematical representation of viscosity of ionic liquid and molecular solvent mixtures at various temperatures using the Jouyban-Acree model

Mathematical Representation of Viscosity of Ionic Liquid + Molecular Solvent Mixtures at Various Temperatures Using the Jouyban–Acree Model

Article on mathematical representation of viscosity of ionic liquid and molecular solvent mixtures at various temperatures using the Jouyban-Acree model

Effects of Analytical Procedures on the Repeatability of Malondialdehyde Determinations in Biological Samples

Background: Malondialdehyde (MDA) is a commonly used biomarker of oxidative stress in clinical studies and has been measured in many pathological conditions during last decades. Different analytical methods have been reported for determination of MDA in biological samples in which MDA was adducted with thiobarbituric acid (TBA) to produce more sensitive chromophore and also convert it to a fluorescent compound. In spite of the routine applications of this derivatization and subsequent analysis of MDA in biomedical studies, its reliability, repeatability and reproducibility is questionable. The aim of this work is to investigate the effects of some factors on the repeatability of MDA determinations in standard solutions and also in plasma samples using spectroscopic method. Methods: MDA-TBA adduct is prepared in standard solutions and the effects of pH, temperature, reaction time, open, closed and reflux systems and the ratio of MDA and TBA is investigated by measuring the absorbance of the solution at 532 nm. These effects are also investigated in human plasma samples. Results: The best results are obtained at pH 2.5, temperature of 70 °C, reaction time of 150 minutes, reflux system and ratio of 2. Conclusion: Using the optimized conditions are resulted in better repeatability

Composition and Temperature Dependence of Density, Surface Tension, and Viscosity of EMIM DEP/MMIM DMP + Water + 1‑Propanol/2-Propanol Ternary Mixtures and Their Mathematical Representation Using the Jouyban–Acree Model

Room temperature ionic liquids (RTILs) have been ascribed as alternative solvents in separation processes or chemical reactions. This research is concerned with the study of density, ρ, viscosity, η, and surface tension, σ, over the mole fractions of (0.1000 to 1.000) mol and temperature from (293.15 to 333.15) K for ternary mixtures of 1-ethyl-3-methylimidazolium diethylphosphate (EMIM DEP)/1,3-dimethylimidazolium dimethylphosphate (MMIM DMP), water, and 1-propanol/2-propanol. As the temperature increased, surface tension and density results for all the multicomponent mixtures show a linear descending trend. Adversely, viscosity results indicate polynomial descending trend. At the whole ranges of temperature, the density, surface tension and viscosity data show a significant gap between mole fractions of ionic liquid. These experimental results have been evaluated and the most prominent polynomial or linear regressions were obtained. The most prominent correlation for density and surface tension for all four systems were obtained using a linear equation. In contrast, the best correlation for viscosity data was obtained using a second order polynomial equation. On the other view, the experimental density and surface tension data decrease linearly with mole fraction of ionic liquid. The Jouyban–Acree model was used to correlate the density, surface tension, and viscosity of the studied mixtures at different temperatures. The accuracy of the model was evaluated and the absolute percentage error (APER) for each correlation was less than 6%