Piezoelectric immunosensor with gold nanoparticles enhanced competitive immunoreaction technique for 2,4-dichlorophenoxyacetic acid quantification

The competitive immunoreaction technique for the detection of 2,4-dichlorophenoxyacetic acid(2,4-D) was described in this paper based on quartz crystal microbalance (QCM) with gold nanoparticles enhanced surfaces. The results showed the response of the sensor has a good linear relationship with 2,4-D concentrations in the range of 13.3–666.7 ng/mL with a detection limit at about 13.0 ng/mL. This work also provides a promising alternative approach for immuno-detection of other small molecules. The sensor could be regenerated under mild conditions simply by immersing the sensor into glycine buffer solution to break the antibody-antigen linkage. It was found that the proposed sensor could be reused at least nine runs without obvious loss of sensitivity.