TY - JOUR
T1 - Prediction of the zeta potentials and ionic descriptors of a silica hydride stationary phase with mobile phases of different pH and ionic strength
AU - Kulsing, Chadin
AU - Yang, Yuanzhong
AU - Matyska, Maria Teresa
AU - Pesek, Joseph Joel
AU - Boysen, Reinhard I
AU - Hearn, Milton Thomas William
PY - 2015
Y1 - 2015
N2 - In this study, the zeta potentials of a silica hydride stationary phase (Diamond Hydride™) in the presence of different water–acetonitrile mixtures (from 0–80% (v/v) acetonitrile) of different ionic strengths (from 0–40 mM) and pH values (from pH 3.0–7.0) have been investigated. Debye–Hückel theory was applied to explain the effect of changes in the pH and ionic strength of these aqueous media on the negative zeta potential of this stationary phase. The experimental zeta potentials of the Diamond Hydride™ particles as a function of acetonitrile content up to 50% (v/v) correlated (R2 = 0.998) with the predicted zeta potential values based on this established theory, when the values of the dissociation constant of all related species, as well as viscosity, dielectric constant and refractive index of the aqueous medium were taken into consideration. Further, the retention behavior of basic, acidic and neutral analytes was investigated under mobile phase conditions of higher pH and lower ionic strength. Under these conditions, the Diamond Hydride™ stationary phase surface became more negative, as assessed from the increasingly more negative zeta potentials, resulting in the ion exchange characteristics becoming more dominant and the basic analytes showing increasing retention. Ionic descriptors were derived from these chromatographic experiments based on the assumption that linear solvation energy relationships prevail. The results were compared with predicted ionic descriptors based on the different calculated zeta potential values resulting in an overall correlation of R2 = 0.888. These studies provide fundamental insights into the impact on the separation performance of changes in the zeta potential of the Diamond Hydride™ surface with the results relevant to other silica hydride and, potentially, to other types of stationary phase materials
AB - In this study, the zeta potentials of a silica hydride stationary phase (Diamond Hydride™) in the presence of different water–acetonitrile mixtures (from 0–80% (v/v) acetonitrile) of different ionic strengths (from 0–40 mM) and pH values (from pH 3.0–7.0) have been investigated. Debye–Hückel theory was applied to explain the effect of changes in the pH and ionic strength of these aqueous media on the negative zeta potential of this stationary phase. The experimental zeta potentials of the Diamond Hydride™ particles as a function of acetonitrile content up to 50% (v/v) correlated (R2 = 0.998) with the predicted zeta potential values based on this established theory, when the values of the dissociation constant of all related species, as well as viscosity, dielectric constant and refractive index of the aqueous medium were taken into consideration. Further, the retention behavior of basic, acidic and neutral analytes was investigated under mobile phase conditions of higher pH and lower ionic strength. Under these conditions, the Diamond Hydride™ stationary phase surface became more negative, as assessed from the increasingly more negative zeta potentials, resulting in the ion exchange characteristics becoming more dominant and the basic analytes showing increasing retention. Ionic descriptors were derived from these chromatographic experiments based on the assumption that linear solvation energy relationships prevail. The results were compared with predicted ionic descriptors based on the different calculated zeta potential values resulting in an overall correlation of R2 = 0.888. These studies provide fundamental insights into the impact on the separation performance of changes in the zeta potential of the Diamond Hydride™ surface with the results relevant to other silica hydride and, potentially, to other types of stationary phase materials
KW - Aqueous normal phase chromatography
KW - Silica hydride stationary phases
KW - Zeta potential measurements
KW - Debye–Hückel theory
KW - Linear solvation energy relationships
KW - Ionic descriptors
UR - http://goo.gl/9mjvxD
U2 - 10.1016/j.aca.2014.10.055
DO - 10.1016/j.aca.2014.10.055
M3 - Article
VL - 859
SP - 79
EP - 86
JO - Analytica Chimica Acta
JF - Analytica Chimica Acta
SN - 0003-2670
ER -