Application of dynamic capillary isoelectric focusing to the analysis of human hemoglobin variants

Capillary isoelectric focusing (CIEF) with electro-osmotic zone displacement of normal and pathological hemoglobins (Hb) is reported. CIEF is performed in untreated, open-tubular, fused-silica capillaries of 75 microns internal diameter using methylcellulose for dynamic column conditioning. After direct injection of hemolysates mixed with carrier ampholytes, high resolution separation of Hb variants, including Hb A1c, A, F, D, S, E and A2, is obtained, this permitting unambiguous characterization of Hb patterns of normal adults, newborns, patients with diabetes, different hemoglobinopathies and thalassemia syndromes. Qualitatively, the CIEF data compare well with those obtained by gel isoelectric focusing and high-performance liquid chromatography. CIEF is demonstrated to be a simple, rapid and fully instrumental approach to Hb analysis. Run times of less than 20 min make CIEF an attractive method for routine Hb investigations and screening programs.