A dye@MOF crystalline probe serving as a platform for ratiometric sensing of trichloroacetic acid (TCA), a carcinogen metabolite in human urine

Abstract

In this work, a microporous luminescent probe based on a fluorescein (FS) dianion dye functionalized metal–organic framework (MOF), FS@1, is designed to effectively detect TCA in human urine. We prepared the hybrid material by introducing the dianion dye into a Zn-based MOF ([Zn₂(Tipa)₂(OH)]·3NO₃·12H₂O, 1) by post-synthetic ion exchange. This study shows that the luminescence intensity ratio of the peaks at 518 nm and 411 nm correlates well linearly to the concentration of TCA with a rapid response time of less than 30 seconds while disregarding the interference of other coexisting species in urine. It also exhibits excellent sensitivity with a detection limit of 1.22 ppm/7.46 μmol L⁻¹. Furthermore, a portable paper-based probe for the convenient detection of TCA has been designed, which exhibits a distinct fluorescence change.