title: Applicability of linear and nonlinear retention-time models for reversed-phase liquid chromatography separations of small molecules, peptides, and intact proteins.
abstract: The applicability and predictive properties of the linear solvent strength model and two nonlinear retention-time models, i.e., the quadratic model and the Neue model, were assessed for the separation of small molecules (phenol derivatives), peptides, and intact proteins. Retention-time measurements were conducted in isocratic mode and gradient mode applying different gradient times and elution-strength combinations. The quadratic model provided the most accurate retention-factor predictions for small molecules (average absolute prediction error of 1.5%) and peptides separations (with a prediction error of 2.3%). An advantage of the Neue model is that it can provide accurate predictions based on only three gradient scouting runs, making tedious isocratic retention-time measurements obsolete. For peptides, the use of gradient scouting runs in combination with the Neue model resulted in better prediction errors (<2.2%) compared to the use of isocratic runs. The applicability of the quadratic model is limited due to a complex combination of error and exponential functions. For protein separations, only a small elution window could be applied, which is due to the strong effect of the content of organic modifier on retention. Hence, the linear retention-time behavior of intact proteins is well described by the linear solvent strength model. Prediction errors using gradient scouting runs were significantly lower (2.2%) than when using isocratic scouting runs (3.2%).
authors.affiliation: Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Eva
authors.initials: E
authors.lastname: Tyteca
authors.affiliation: Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Jelle
authors.initials: J
authors.lastname: De Vos
authors.affiliation: Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.|Faculty of Chemical Technology, Department of Analytical Chemistry, University of Pardubice, Pardubice, Czech Republic.
authors.forename: Nikola
authors.initials: N
authors.lastname: Vankova
authors.affiliation: Faculty of Chemical Technology, Department of Analytical Chemistry, University of Pardubice, Pardubice, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Cesla
authors.affiliation: Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Gert
authors.initials: G
authors.lastname: Desmet
authors.affiliation: Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Eeltink
mesh_terms: D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D008958:Models, Molecular; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification*; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D010455:Peptides; D010636:Phenols; D011506:Proteins
keywords: Linear solvent strength model; Method development; Neue-Kuss model; Retention-time prediction; Selectivity