Capillary Electrophoresis-Based Immunoassay for Cortisol in Serum

• Published in: Analytical chemistry (Washington) Vol. 67; no. 3; pp. 606 - 612
• Main Authors: Schmalzing, Dieter, Nashabeh, Wassim, Yao, Xian-Wei, Mhatre, Rohin, Regnier, Fred E, Afeyan, Noubar B, Fuchs, Martin
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.02.1995
• Subjects: Analysis of complex biological substances; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Blood and biological fluids; Electrophoresis - methods; Fundamental and applied biological sciences. Psychology; Hydrocortisone - blood; Immunoassay; Reproducibility of Results; Spectrophotometry, Ultraviolet; Biological fluid; Separation method; Reproducibility; Clinical biology; Electrophoresis; Serum; Cortisol; Detection; Blood; Capillary tube; Quantitative analysis
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac00099a019

A competitive immunoassay for cortisol based on capillary electrophoresis (CE) and laser-induced fluorescence is described. The work involved the production of assay reagents and the development of separation conditions allowing for routine analysis of serum samples. Fluorescein-labeled cortisol was synthesized and purified. Fab fragments were produced from mouse monoclonal anticortisol antibody and purified using a POROS cation exchange chromatography column. After incubation of these reagents with serum, free and bound labeled antigen were separated by CE with high reproducibility. No prior sample cleanup of the serum samples was necessary. Serum calibration curves were established and used for the quantitation of cortisol in serum. The results demonstrate feasibility for a cortisol assay based on CE operating directly on serum samples.