LASER FLUORESCENCE IMMUNOASSAY OF INSULIN

A new technique is described for a competitive binding assay. Bound and free fluorescent-labeied antigen are separated by high pressure liquid chromatography and detected by laser fluorimetry. This method is illustrated in the detection of insulin in well-characterized buffer solutions. Fluorescein isothiocyanate serves as the fluorescent tag, a gel filtration column permits a separation on the basis of molecular size, and the 488-nm line of a CW argon ion laser provides the excitation. The best detection limit of insulin is 0.4 ng/mL. The sensitivity of laser fluorescence immunoassay is found to be comparable to that of radioimmunoassay. © 1979, American Chemical Society. All rights reserved.