Portable smartphone-assisted RGB-dependent ratiometric sensing platform for the detection of tetrachloro-p-benzoquinone in river samples

Tetrachloro-p-benzoquinone (TC-PBQ) can be harmful to the environment as a pesticide residue, but its analytical detection has been largely neglected. In this work, a smartphone-assisted RGB-dependent TC-PBQ ratiometric sensing platform for rapid recognition is introduced. Here, the red-emitting mercaptopropionic acid-capped CdTe quantum dots (MPA-capped CdTe) as the reaction unit can be quenched by TC-PBQ, while the blue-emitting carbon dots (CDs) as the reference signal remain unchanged. The limit of detection (LOD) of the sensing platform can reach 59 nM in aqueous solution. By constructing an analysis model with the system RBG value, the smartphone-assisted sensor-coated fluorescent test paper can complete the qualitative and quantitative visual detection of TC-PBQ (LOD is 93 nM). The applicability of smartphone-dependent RGB analysis signifi-cantly simplifies and speeds up the operation process, which provides a new analytical method for real-time analysis of TC-PBQ in real samples.