Overcoming common challenges to determine residual impurities using IC in APIs with limited water

Organic solvents are generally not compatible with ion chromatography (IC) systems. The presence of organic solvents in sample diluent when injected onto an ion chromatographic system can cause unwanted chromatography artifacts such as broad baseline interferences or drifting baseline, which can preclude method robustness and accuracy. However, some active pharmaceutical ingredients (APIs) have poor water solubility, leaving the analyst with little choice other than to use organic solvents to attain dissolution.

The approach presented here assists the use of organic solvents for sample preparation and provides a mechanism for the removal of the organic solvents from the chromatographic flow path. This removes all associated chromatographic interferences, thereby providing a good basis for an accurate and robust method.