Dual-emissive dye@MOF composite for ratiometric detection and discrimination of two isomers of tetrachlorobenzenediol

Abstract

Polychlorophenols are widely distributed priority pollutants, but fluorescent sensor targeting of them has rarely been reported. In this work, a dye@MOF composite with dual emission was screened out for the ratiometric fluorescent detection of the two isomers of tetrachlorobenzenediol (o- and p-TCBDs). These two analytes could restrict the vibration of the MOF host through hydrogen bonds and thus enhance its emission, while the fluorescent dye guest was quenched via a photo-induced electron transfer mechanism. This sensor exhibited a good quantification ability (over 100 μM linear response ranges and sub-μM scale DLs) and selectivity (immune to the interference from other chlorophenols and chloroquinones) for TCBDs. It is interesting to observe that, in spite of the similar structures of the two analytes, using the overall intensity change of the two emission bands of the sensor as a criterion, they could be clearly discriminated over the whole tested concentration range. This sensor was successfully applied to TCBD analysis in clinical samples.