Carbon dot embedded photonic crystal molecularly imprinted as dual-mode fluorometric/colorimetric sensor for the determination of sulfadimethoxine in fish

A novel fluorescent membrane based on carbon dot embedded photonic crystal molecularly imprinted polymer (PCMIP@CDs) was developed for fluorometric and colorimetric dual-mode determination of sulfadimethoxine with excellent selectivity, quick response, and reusability. In the presence of sulfadimethoxine, fluorescence quenching and red shift of diffraction peak from PCMIP@CDs were observed because of the photo-induced electron transfer and structural change of PCMIP@CDs, accompanied by a visual color change from blue to green. The fluorescence quenching efficiency and the red-shift of the diffraction peaks were positively correlated with the logarithms of the sulfadimethoxine concentration at 10- 12-10- 5 and 10- 10-10- 5 mol L-1, respectively. The sensor achieved a limit of detection of 0.08 pmol L-1 (fluorescence method) and 2.75 pmol L-1 (colorimetric method, 3 & sigma;, n = 9). The developed PCMIP@CD membrane was applied for the detection of sulfadimethoxine in fish samples with favorable recovery of 84.8-102.9%.