Thermo Fisher Scientific has developed an ion chromatography (IC) method for determining low concentrations of morpholine in linezolid using an eluent generation system with suppressed conductivity detection.
Morpholine is used in the synthesis of linezolid and may be present in the drug product. This approach achieves efficient separation using a high-performance cation-exchange column with a high-purity electrolytically generated methanesulfonic acid eluent.
Application Note 1062: Determination of Morpholine in Linezolid by Ion Chromatography demonstrates that this IC method also allows simultaneous determination of sodium, ammonium, potassium, and other cations present in the sample.
To prevent column contamination by linezolid, this method uses in-line matrix elimination to concentrate trace morpholine on a pellicular cation-exchange concentrator column, followed by removal of the uncharged linezolid with deionized water using a high-precision autosampler and then elution of the morpholine onto the high-performance cation-exchange column.