UNIFAC model as a heuristic guide for estimating retention in chromatography

Solvent Strength Parameters and Retention Factors in Pure Water Using UNIFAC-Predicted Activity Coefficients

“…[4][5][6][7][8][9][10][11] We showed that UNIFAC is generally applicable as a heuristic guide for understanding the magnitude of solute-solvent interactions in gas chromatography and normal and reversed-phase liquid chromatography (RPLC). 12,13 It is fitting in this issue to explicitly recognize the significant contributions made by Eckert et al to the analysis of UNIFAC and to the measurement, collection, and prediction of limiting activity coefficients. [14][15][16][17][18][19][20][21][22][23] UNIFAC combines the UNIQUAC model of solutions 24 and the so-called analytical solution of group concept.…”

“…As we have shown, UNIFAC-based models are not accurate enough, at this stage of its development, to be useful for quantitative prediction of retention. 12,13,30 Because chromatography is able to distinguish between two types of solute molecules that differ in the strength of their interactions with the mobile and stationary phases by only a few calories per mole, there is as yet no general predictive method that suffices for use in chromatography. Nonetheless, UNIFAC is sufficiently accurate for predicting the relative strengths of solvents, the relative retention of solutes, and other important chromatographic properties.…”

“…Nonetheless, UNIFAC is sufficiently accurate for predicting the relative strengths of solvents, the relative retention of solutes, and other important chromatographic properties. 7,8,12,13 Several studies on the application of UNIFAC to predicting retention in RPLC have appeared in the literature. [9][10][11][12][13] Retention prediction and selectivity optimization are important for rapid method development in RPLC.…”

“…7,8,12,13 Several studies on the application of UNIFAC to predicting retention in RPLC have appeared in the literature. [9][10][11][12][13] Retention prediction and selectivity optimization are important for rapid method development in RPLC. 35 However, retention in RPLC is a complicated process [36][37][38][39][40] and depends on many physical and chemical properties of the system such as temperature, [41][42][43] solute molecular properties, 44 stationary-phase characteristics, 45 and mobile-phase properties.…”

“…The UNIFAC ( UNI QUAC f unctional group a ctivity c oefficient) model is an activity coefficient estimation scheme that has found widespread applicability in chemical engineering. − There have been a number of studies on the application of UNIFAC for estimation of retention in gas and liquid chromatography. − We showed that UNIFAC is generally applicable as a heuristic guide for understanding the magnitude of solute−solvent interactions in gas chromatography and normal and reversed-phase liquid chromatography (RPLC). , It is fitting in this issue to explicitly recognize the significant contributions made by Eckert et al to the analysis of UNIFAC and to the measurement, collection, and prediction of limiting activity coefficients. − …”