12 research outputs found
Prediction of thermal properties of ternary systems of 2,2ʹoxybis[propane]+ benzene, toluene, cyclohexane or n-heptane
Prediction of thermal properties of ternary systems of 2,2ʹoxybis[propane]+ benzene, toluene, cyclohexane or n-heptane
Effect of Temperature on the Variation of Retention Time of Unretained Compound and Retention Indices of Some Explosives and Related Compounds Calculated Using a Multiparametric Method in RP-LC
Computer-assisted optimization in the development of high-performance liquid chromatographic methods for the analysis of some explosives and related compounds
Enthalpies of mixing of binary and ternary mixtures containing diisopropylether, benzene and cyclohexane at 303.15 K
Retention Time of Unretained Compound Calculation and Determination of Retention Indices of Some Monosubstituted Benzenes Using a Multiparametric Method in Binary, Ternary and Quaternary Solvent RP-LC Systems
Characterization of stationary phases based on monosubstituted benzene retention indices using correspondence factor analysis and linear solvation energy relationships in RPLC
A Thermodynamic Study of Capillary Electrochromatographic Retention of Aromatic Hydrocarbons on a Lauryl Acrylate Porous Polymer Monolithic Column with Measured Phase Ratio
The phase ratio of a chromatographic system is an important measurement that has long been estimated or calculated, but rarely directly measured. This study utilized a nanoflow liquid chromatography instrument to more accurately measure the phase ratio for a lauryl acrylate porous polymer monolith. Direct measurement of the phase ratio, and its dependence on temperature, allows for a better understanding of the thermodynamics of retention of small analytes. This study investigates the retention of an alkyl benzene series, toluene to octylbenzene, via capillary electrochromatography. The phase ratio was determined to be 0.202 at 303 K and 0.213 at 333 K. Using the directly measured phase ratio, entropic contributions to retention can also be obtained. Therefore, the Gibbs free energy calculations from these measurements and methods can give insight to modes of retention. The free energy of retention for toluene is –3.97 kJ/mol at 303 K and –3.78 kJ/mol at 333 K. The trends for enthalpy, entropy, and Gibbs free energy of transfer show that retention is enthalpically driven in this capillary electrochromatography (CEC) porous polymer monolith system