Rapid simultaneous determination of glucagon and insulin by capillary electrophoresis immunoassays.

A rapid capillary electrophoresis (CE) with laser-induced fluorescence (LIF) competitive immunoassay has been developed for the determination of glucagon in biological mixtures. In the assay, fluorescein-conjugated glucagon is mixed with the sample followed by addition of anti-glucagon. Free and antibody-bound, tagged glucagon could be separated in 3 s using CE to obtain quantitative determination of glucagon with a concentration detection limit of 760 pM. The assay was combined with a previously developed competitive immunoassay for insulin to produce a simultaneous immunoassay for both peptides. The method was used to determine glucagon content of islets of Langerhans.