We combine the use of magnetic particles and Vitamin C-containing chitosan capsules to develop a liquid-phase ELISA technology, where targeted analytes are sandwiched between magnetic particles (intrinsic activity of horseradish peroxidase) and the Vc-containing chitosan capsules (inhibitor), and binding of analytes to antibodies takes place in liquid phase instead of on the walls of the plates in conventional ELISA. Such an approach greatly shortens the diffusion path of analytes in order to reach antibodies and therefore, accelerates the detection speed of the ELISA technology. The technology has great potential for a wide range of applications in medicine, biotechnology, and environmental monitoring industries.