1,4-Dihydroxyanthraquinone-Cu2+ ensemble probe for selective detection of sulfide anion in aqueous solution

Based on the displacement strategy, a new and simple sulfide-selective chemosignaling system was devised using 1,4-dihydroxyanthraquinone (DHAQ)-Cu2+ ensemble. In aqueous solution containing 10% ethanol (HEPES buffer, pH7.4), DHAQ could give rise to a visible yellow-to-pink color change with the addition of Cu2+. The resulting pink solution changed to yellow upon subsequent addition of sulfide anion. Moreover, DHAQ displays an ON-OFF-ON mode fluorescence change with alternately added Cu2+ and S2-. Experimental results show a low interference response towards other common anions. The selective switch-on fluorescence response of the sensing ensemble to S2- makes it suitable for sensing of S2- in aqueous solution. The detection limit is 5.98 x 10(-8) M.