Abstract: A new method for the determination of Cd in the water with a wireless magnetoelastic immunosensor was introduced. In the method, the specific binding of antigen with the antibody made precipitation adhere to the surface of the immunosensor and resulted in a decrease in the resonance frequency of the magnetoelastic foil. The shift of the resonance frequency was related to the concentration of Cd. The influence of some factors such as polyethylene imine dosage, glutaraldehyde dosage and reaction time on the determination was discussed. At the optimized conditions, the linear range for the determination of Cd was in the range of 0.90~10.0 μg/L, with the detection limit of 0.42 μg/L. The proposed method was applied successfully to the determination of Cd in water samples with the recoveries of 96.5%~103.6%. The determination results are basically consistent with that of dithizone colorimetric method.

Key words: Cd, wireless magnetoelastic immunosensor, immunization, wireless detection