摘要
To develop a highly sensitive, specific, and simple immunoassay with little influence from admixtures, we proposed an ultrasensitive heterogeneous immunoassay using gold ultrafine particles and photothermal deflection method. The immunological samples were dropped on a membrane, and the antibody-coated gold particles were adsorbed on the membrane through an immunoreaction with the sample. The sample was determined by measuring the distribution of the gold particles. This method was applied to human IgG, and the lower detection limit was 20 pg. © 1991, The Japan Society for Analytical Chemistry. All rights reserved.