HPLC Separation of Drugs

Mixed-mode chromatography allows to separate various hydrophobic and hydrophilic drugs in one HPLC method. Presence of at least two mechanism of retention allows adjust selectivity of separation by changing three parameters: amount of acetonitrile, buffer concentration and buffer pH. Seven common drugs are separated on a Primesep C trimodal HPLC column in gradient method. Method provides alternative selectivity to traditional reversed-phase chromatography. Operational range in which basic compounds are retained the most is from pH 3 to 5. At higher pH, longer retention can be achieved. Mixed-mode chromatography provides longer retention and better peak shapes for basic and acidic analytes. Method can be used in analysis of drugs and pharmaceuticals.


Column Primesep C, 4.6×150 mm, 5 µm, 100A
Mobile Phase MeCN
Buffer Formic Acid
Flow Rate 1.0 ml/min
Detection UV, 250 nm




Class of Compounds
Drug, Analgetic, Acid, Hydrophilic, Ionizable,
Analyzing Compounds Norphenylephrine, Norephedrine, Pseudoephedrine, Doxylamine, Pyrilamine, Dextromethorphan, Trimipramine

Application Column

Primesep C

The Primesep family of mixed-mode columns offers a wide variety of stationary phases, boasting unprecedented selectivity in the separation of a broad array of chemical compounds across multiple applications. Corresponding Primesep guard columns, available with all stationary phases, do not require holders. SIELC provides a method development service available to all customers. Inquire about our specially-tailored custom LC-phases for specific separations.

Select options
Application Analytes:
Pseudoephedrine (PSE)

Application Detection:
UV Detection
SIELC Technologies usually develops more than one method for each compound. 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 research@sielc.com so we can ensure you get optimal results for your compound/s of interest.