Analysis of Antibiotic Josamycin and Related Impurities in Mixed-Mode Chromatography


Condition 1

Column Obelisc R, 4.6×150 mm, 5 µm, 100A
Mobile Phase Gradient MeCN – 5-30%, 10 min, 5 min hold
Buffer Gradient Formic Acid – 0.05%-0.3%, 10 min, 5 min hold
Flow Rate 1.0 ml/min
Detection UV, 250 nm

Josamycin is a macrolide antibiotic effective against gram-positive bacteria. It is highly polar and does not retain well on reversed-phase columns. The Mixed-mode column Obelisc R was used to retain josamycin and its related impurities.  Primesep D was also used to analyze josamycin impurities because Primesep D does not retain high-molecular weight plasma components. This method is compatible with LC/MS, prep chromatography and can be used for analysis of josamycin in biofluids.

Condition 2

Column Primesep D, 4.6×150 mm, 5 µm, 100A
Mobile Phase Gradient MeCN – 5-50%, 10 min, 3 min hold
Buffer H2SO4 – 0.1%
Flow Rate 1.0 ml/min
Detection UV, 250 nm



Class of Compounds
 Antibiotic, Drug, Hydrophobic, Ionizable
Analyzing Compounds  Josamycin


Application Column

Obelisc R

SIELC has developed the Obelisc™ columns, which are mixed-mode and utilize Liquid Separation Cell technology (LiSC™). These cost-effective columns are the first of their kind to be commercially available and can replace multiple HPLC columns, including reversed-phase (RP), AQ-type reversed-phase, polar-embedded group RP columns, normal-phase, cation-exchange, anion-exchange, ion-exclusion, and HILIC (Hydrophilic Interaction Liquid Chromatography) columns. By controlling just three orthogonal method parameters - buffer concentration, buffer pH, and organic modifier concentration - users can adjust the column properties with pinpoint precision to separate complex mixtures.

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Primesep D

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.

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Application Analytes:

Application Detection:
ELSD 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.