Quantitative capillary electrophoresis assay for the proteolytic stability of luteinizing hormone-releasing hormones

A rapid and simple capillary electrophoresis (CE) assay for measuring the stability of luteinizing hormone-releasing hormone (LHRH) analogues in the presence of intestinal enzymes has been developed and validated. Buffer pH and sample stacking were important factors in controlling resolution and reproducibility. The CE assay for human (h) and salmon LHRH analogues between 0.05 and 0.25 mM was linear for peak height versus concentration (r2>0.99). Analysis of hLHRH at 0.1 mM had an intra-day relative standard deviation of 1.25% and an inter-day relative standard deviation of 5.0%. The method was applied to the stability of LHRH analogues in salmon intestinal digests.