HPLC Separation of Acetaminophen, Phenylephrine, and Diphenhydramine

Primesep C separates acetaminophen (paracetamol), phenylephrine, and diphenhydramine– common over-the-counter cold and flu medication ingredients such as Tylenol products—by either an acetonitrile or phosphoric acid gradient. The HPLC separation uses a mobile phase of water, acetonitrile (MeCN, ACN), and phosphoric acid with ultraviolet (UV) detection at 210 nm.


Column Primesep C, 4.6×150 mm, 5 µm, 100A
Mobile Phase MeCN
Buffer H3PO4
Flow Rate 1.0 ml/min
Detection UV, 210 nm




Class of Compounds
Drug, Analgetic, Acid, Hydrophilic, Ionizable,
Analyzing Compounds Acetaminophen, Pseudoephedrine, Diphenhydramine

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:
Acetaminophen (Paracetamol)

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.