Comparison of the Separation of Polar Drugs on Obelisc R and Zorbax SB-AQ

Common hydrophobic basic and hydrophilic basic drugs are separated by mixed-mode chromatography with greater selectivity and resolution than traditional reversed-phase column. Drugs are retained by combination of reversed-phase and cation-exchange mechanisms. Retention time is controlled by amount of acetonitrile, buffer concentration and buffer pH. Available detection techniques are based on buffer selection and include UV, Evaporative Light-Scattering Detector (ELSD), Corona (CAD), LC/MS, etc. This HPLC method can be adopted as general approach for analysis of drugs and pharmaceuticals.

SIELC Technologies usually develops more than one method for each compound on our website. Therefore, this particular method may not be the best available method from our portfolio for your specific application. Before you decide to implement this method in your research, please send us an email to so we can ensure you get optimal results for your compound of interest.
Application Analytes:

Pseudoephedrine (PSE)

Application Detection:
UV Detection