6533b82cfe1ef96bd128fd9a

RESEARCH PRODUCT

Quantitative retention—structure and retention—activity relationship studies of ionic and non-ionic catecholamines by micellar liquid chromatography

subject

description

When ionic surfactants are used as mobile phases in micellar liquid chromatography, MLC, the retention of compounds is governed by hydrophobic and electrostatic forces. In the absence of electrostatic effects, the hydrophobicity of a compound is the predominant factor affecting its retention and its interaction with micelles. Because both interactions should be considered for ionic compounds, a novel retention model is proposed which includes the hydrophobicity of a compound and the molar fraction of its charged form. High correlations between the logarithm of the capacity factors and structural parameters were obtained for ionic compounds with different degrees of ionization. The effect of the nature and composition of the mobile phase (pH, concentration of surfactant and modifier) was studied. The modelling of the retention of compounds as a function of physico-chemical parameters and experimental variables was established by means of multivariate regression methods (MLR, PLS). In addition, a predictive model for estimating the hydrophobicity of catecholamines is proposed. Finally, quantitative retention-activity relationships in MLC were also investigated for catecholamines.