USP Methods for the Analysis of Ibuprofen using a Legacy L1 Column

Application Notes: Ibuprofen is the most commonly used analgesic. It is a vasoconstrictor and fever reducer. According to the USP methods, ibuprofen contains no less than 97% and no more than 103% ibuprofen based on a dried basis. The USP HPLC method for the separation of procainamide was developed on Legacy L1 column according to the US Pharmacopeia methodology. L1 classification is assigned to reversed-phase HPLC column containing Ci18 ligand. Support for the material is spherical silica gel with particles size 3-10 um and pore size of 100-120A. Resolution between critical pairs corresponds to rules and specifications of USP.

Application Columns: Legacy L1 C18 HPLC column

Application compounds: Ibuprofen and benzophenone

Mobile phase: .01M H3PO4/MeCN (55/45)

Detection technique: UV

Reference: USP35: NF30


Column Legacy L1, 4.6×150 mm, 5 µm, 100A
Mobile Phase MeOH/H2O – 45/55%
Buffer H3PO4
Flow Rate 1.5 ml/min
Detection UV, 230 nm



Class of Compounds
Drug, Nonsteroidal anti-inflammatory drug, Hydrophobic, Ionizable, Neutral
Analyzing Compounds Ibuprofen, benzophenone


Application Column

SIELC Legacy L1 HPLC column

Legacy L1

SIELC's family of Legacy columns is based on the United States Pharmacopeia's (USP) published chromatographic methods and procedures. Numerous brands have columns used in USP reference standards and methods. USP has created various designations to group together columns with similar types of packing and properties in the solid phase. SIELC's Legacy columns adhere to these strict requirements and properties, allowing you to easily replace older columns that are no longer available without needing to significantly modify your method or SOPs.

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Application Analytes:

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 so we can ensure you get optimal results for your compound/s of interest.