A relay strategy for the mercury (II) chemodosimeter with ultra-sensitivity as test strips

Abstract

A relay strategy has been proposed to design a new Hg2+ chemodosimeter (TPE-S), by coupling Hg 2+-promoted deprotection reaction with ketone-enol isomerization, realizing the multistage amplifying effect. Changes in both of color and fluorescence could occur immediately, and TPE-S displayed high selectivity for Hg2+, other metal ions (Ag+, Fe3+, Cu2+, Pb2+, Co2+, Cr3+, Al3+, Cd2+, Mg2+, Mn2+, Ba2+, Fe 2+, Ca 2+, Ni 2+, Zn 2+, Li+, K+ and Na+) gave nearly no disturbance to the sensing process. When fabricated as test strips similar to pH-indicator papers, immediate color change from colorless to purple could be visually observed by naked-eyes without the aid of any additional equipment, with the detection limit as low as 1 × 10-7 M (Hg 2+ in aqueous solution). Due to its easy synthesis, high selectivity and sensitivity, combined with the portable test strips, TPE-S could be developed as a convenient and cost-effective tool for the detection of Hg 2+ in on-site inspections.