Capillary zone electrophoresis–mass spectrometry as a tool in the stability research of the luteinising hormone-releasing hormone analogue goserelin

Abstract

A capillary zone electrophoresis (CZE)–MS system for peptide analysis was developed, characterised and applied in the stability research of goserelin, a luteinising hormone-releasing hormone analogue. 10% acetic acid was used as running solution. An important aspect of this CZE–MS system is its relative insensitivity to injection volume size and ions in sample solutions. As a result of the low pH (2.3) of the running solution, the endoosmotic flow was minimal, resulting in mainly electrophoretic movement and, therefore, relatively high resolution. Degraded samples of goserelin at pH 5 and 9 were subjected to analysis with this CZE–MS system. Information was obtained about the degradation of the C-terminal semi-carbazide group. A major difference between CZE and LC is that goserelin epimers are not separated in the CZE system, whereas they are in the RP-HPLC system.