Separation of Drugs in Mixed-Mode HPLC

Obelisc R column can be successfully used for analysis of hydrophobic and hydrophilic basic and acidic drugs and corresponding counter-ions. This approach can be used for analysis of various cold and cough composition, pain killers, and other prescription and over-the-counter medications. Within pH 3-5, both cation- and anion mechanism are present on the column, along with hydrophobic interaction. Selectivity of this mixed-mode separation is controlled by the amount of acetonitrile, buffer concentration and buffer pH. Method is robust and reproducible, and can be used as a common HPLC method for analysis of drug molecules and compositions.


Column Obelisc R, 4.6x150 mm, 5 µm, 100A
Mobile Phase MeCN
Buffer AmFm
Flow Rate 1.0 ml/min
Detection UV, 270 nm


Class of Compounds Drug, Analgetic, Acid, Hydrophilic, Ionizable,
Analyzing Compounds Maleate, Chlorpheniramine, Dextromethorphan

Application Analytes:
Acetaminophen (Paracetamol)