PEPTIDE IMMUNOASSAY USING CAPILLARY ELECTROPHORESIS A WITH LASER-INDUCED FLUORESCENCE DETECTION

A recently developed format for competitive immunoassay involves capillary electrophoresis with laser-induced fluorescence immunodetection (CE LIF-ID) of an antigen labeled with a fluorescent dye. The resolving power of CE separates bound from free antigen, eliminating the need for a solid phase. The specificity of LIF detection results in uncomplicated and easy-to-interpret electropherograms, even when analytes in complex matrices such as serum are analyzed. CE LIF-ID was applied to the analysis of a model peptide, angiotensin II (AT II), spiked into human serum. The result is a rapid (3-min separation times) and accurate (104% recovery at 5 ng/mL) assay. The limit of detection was 2 x 10(-10)-2 x 10(-9) M. In addition, the CE format offers reduced method development time, since there is no need to find conditions and materials for stable and reproducible immobilization of antibodies or antigens.