Determination of IgG in human serum by solid substrate room temperature phosphorescence-immunoassay

On many kinds of solid substrate, such as polyamide membrane, cellulose ace tate membrane etc., the specific immunological reaction between the human i mmunoglobulin G(IgG) and the goat antihuman antibody labeled with isothiocy anate fluorescein (GAHAb*) can be carried into practice quantitatively. The antigen-antibody conjugate remained excellent room temperature phosphoresc ence (RTP) properties of isothiocyanate fluorescein. The conditions for imm unological reaction and RTP measurement were optimized. A convenient solid substrate room temperature phosphorescence immunoassay(SS-RTP-IA) method fo r determination of the IgG has been developed. The linear dynamic range of the method is 0.624-20 pg/spot(o.4 muL) and the calculated detection limit by the methodology of IUPAC is 0.32 pg/spot. The regression equation is Del taI(p) = 31.4+46.2 lg[c(Ag)/pg], correlation coefficient r = 0.999, n = 6. The method was used for the determination of IgG in normal human serum with good satisfactory results. The analytical recoveries are 96%-104% for seve n replicates and the relative standard deviations are 2.6%-2.9%.