A simple on-line detection system based on fiber-optic sensing for the realtime monitoring of fixed bed adsorption processes of molecularly imprinted polymers.

•On-line, realtime measurement of fixed bed adsorption process was proposed based on fiber-optic sensing.•The method could provide breakthrough curves with whole data.•High accuracy and reproducibility with less time and labor cost were attained owing to on-line and automatic process.•Simple instrumentation with easy operation greatly accelerated analysis process and satisfied wider practical needs.•The imprinted polymers demonstrated great potential application in the treatment of 2,4-D wastewater.