A novel indirect inhibitive immunoassay for sulfamethoxazole

A new indirect inhibitive immunoassay using surface plasmon resonance (SPR) coupled with molecularly imprinted polymer (MIP) was developed. A sulfamethoxazole (SMX) MIP coating capillary was produced and used as an in-tube solid phase extraction (SPE) device. The MIP coating formed a nanometer film on the inner wall of the capillary. The anti-SMX mono-antibody was inhibited by SMX extracted by the MIP coating in a dose-dependent manner. The calibration curve was generated by linear fit over the range of 0.04–10.00 ng/mL. The limit of detection was 0.01 ng/mL. This method has high sensitivity and can be performed automatically.