A molecularly imprinted sensor based on an electrochemiluminescent membrane for ultratrace doxycycline determination

A new molecularly imprinted sensor was developed based on an electroluminescent molecularly imprinted polymer (MIP) membrane and used for doxycycline determination. The MIP was prepared by electropolymerization of pyrogallol doped with alizarin red. An electrochemiluminescence (ECL) signal was produced by the oxidation of the poly-pyrogallol polymer and reaction with alizarin red. The luminescence intensity was enhanced by doxycycline molecules which were re-adsorbed in cavities in MIP due to the energy transfer of the doxycycline oxidized intermediate to alizarin red. The changes of ECL intensities were linear with the concentrations of doxycycline in the range of 2 × 10−10 to 5 × 10−8 mol L−1. The detection limit was 5.17 × 10−11 mol L−1. This method was utilized to determine doxycycline residuals in fish muscles with satisfactory results.