Electrophoresis of opioid peptides on columns with agarose suspension

Opioid peptides have been fractionated by column electrophoresis in agarose suspension. The procedure provides a high resolution efficiency and compares favorably with high-performance liquid chromatography. Peptides were recovered from the column in 70% or higher yields when run in the femtomole to the nanomole range. By choosing different pHs it is possible to get complete resolution of a number of different endorphins. The electrophoreses were performed in volatile buffers, which are easily evaporated, and the residues are suitable for direct screening by radioreceptor- or radioimmunoassays. In combination with these assays the separation procedure makes it possible to detect and identify very low concentrations of endorphins in samples of biological origin.