Smartphone-Assisted Quinoline-Based Chromogenic Probe for the Selective Detection of Hg2+ in Protic Media

摘要

High selectivity and sensitivity detection of Hg2+ in aqueous environment by the naked-eye has always been a challenge.In this paper,a simple ligand based on 2-(hydroxymethyl)quinolin-8-ol(L)was synthesized and its structure was confirmed by NMR,IR and mass analysis.The probe L showed distinct colorimetric upon interaction with Hg2+ in CH3OH-H2O(8:2,v/v)media.The ligand L exhibit unique absorbance band at 243 nm due to ligand-to-ligand charge transfer(LLCT).Upon interaction with Hg2+,the L formed new UV-Vis bands at 269 and 316 nm due to ligand-to-metal charge transitions(LMCT).The UV-Vis spectral studies indicate the formation of a 1:1 host-guest complex between the L and Hg2+ with an association constant of 8.6×10~4 M 1.The ligand L can work in the pH range of 3-8 without interfering with other competing ions.The detection limit of Hg2+ can reach a concentration of as low as 0.13 μM(2.6 ppb)with high selectivity,even in a solution containing diverse metal ions.Besides,the selective colour change of L with Hg2+ was integrated with smartphone to monitor the change in RGB tool and test paper kit.The binding mechanism of L with Hg2+ was studied by using ~1HNMR,SEM and TDDFT analysis.Overall,ligand L demonstrates a promising and potential for the detection of toxic contaminate in aqueous environment.