Immobilized antibody-based flow type enzyme immunosensor for determination of human serum albumin

A flow-type enzyme immunosensor was prepared for the electrochemical determination of human serum albumin (HSA). The immunosensor was constructed from the immobilized antibody (anti-HSA IgG) reactor and an oxygen electrode. The immunochemical reaction of catalase-labelled antibody with HSA was completed with 30 min. After the immunochemical reaction, hydrogen peroxide solution was injected into the system and a peak current was obtained within 2 min. A linear relationship was observed between the current increase and the logarithm of HSA concentration in the range 10^-8-10^-6 g ml^-1. The minimum measurable concentration was 10^-8 g ml^-1. The current increase was reproducible with 10% of the relative errors when a sample solution containing 10^-7 g ml^-1 of HSA was used. The minimum measurable concentration increased to 10^-9 g ml^-1 when hydrogen peroxide was recycled for 5 min in the reactor system. The immobilized antibody reactor could be reused. HSA in human serum was determined by the system proposed.