PRECIPITATION FLOW-INJECTION IMMUNOASSAY FOR HUMAN-IMMUNOGLOBULIN-G

The development of a precipitation flow injection immunoassay is descr ibed, This approach is based on the immunoprecipitin reaction, whereby the precipitate formed by binding bf the sample antigen (HIgG) to flu orescein-labelled antibodies is retained on a filter built in on-line in a flow-injection system, After dissolving the precipitate with sodi um hydroxide solution the liberation of fluorescein-labelled antibodie s results in a fluorescence signal that is directly proportional to th e concentration of HIgG. The instrumental set-up is very simple and fu lly automated, One assay cycle takes about 10 min, The RSD ranged betw een 1 and 3%, depending on concentration, The detection limit was abou t 140 fmol, The recovery from spiked serum samples was between 96 and 102%.