Effect of pH on Retention of Basic Compounds on Primesep C Columns

Method for separation of components of cough medication shows how retention for acetaminophen, phenylephrine and guaifenesin is controlled. Order of elution for compounds can be changed based on composition of the mobile phase. The method is compatible with UV, ELSD and LC/MS and can be used for quantitation of drugs in formulation. Primesep C mixed-mode HPLC column is ideal candidate for analysis of cough compositions. Basic compounds are well retained in mixed-mode chromatography without use of ion-pairing reagents. Several companies validated this approach. The method is reproducible and robust and can be used in both production environments and R&D. This HPLC method can be adopted as general approach for analysis of basic compounds in various mixtures.


Column Primesep C, 3x50 mm, 5 µm, 100A
Mobile Phase MeCN
Buffer AmAc
Flow Rate 0.5 ml/min
Detection UV, 270 nm


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

Application Analytes:
Acetaminophen (Paracetamol)