SUSPENSION OF FINE MAGNETIC PARTICLES ANTIGEN-ANTIBODY WITH IMMOBILIZED AND METHOD FOR MEASURING CONCENTRATION OF ANTIGEN OR ANTIBODY BY USING SAID SUSPENSION

摘要

PURPOSE:To permit preservation of a liquid suspension for a relatively long period of time before use by dispersing fine magnetic particles of 50-500Angstrom grain size immobilized with an antigen or antibody into an aq. salt soln. contg. a surface active agent to prepare said liquid suspension. CONSTITUTION:This liquid suspension is prepd. by dispersing fine magnetic particles of 50-500Angstrom grain size with immobilized antigen or antibody into >=5ml (per mg of fine magnetic particle) of isotonic aq. salt soln. with concn. of surface active agent >=0.5wt%. The grain size of fine magnetic particles is preferably in a 100-300Angstrom range. The flocculation operation by an external magnetic field is not possible or an extremely strong magnetic field is required and such is not practicable if the grain size of fine magnetic particles is below 50Angstrom . Long-time maintenance of the stable dispersion state is difficult if the grain size exceeds 500Angstrom . The concn. of the surface active agent in the aq. isotonic salt soln. is preferably 1.0-5.0wt%.