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

A relay strategy has been proposed to design a new Hg(2+) 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 Hg(2+), other metal ions (Ag(+), Fe(3+), Cu(2+), Pb(2+), Co(2+), Cr(3+), Al(3+), Cd(2+), Mg(2+), Mn(2+), Ba(2+), 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.