Highly selective and sensitive optical probe for Cu2+ based on a water-soluble isatin derivative dye

The colorimetric chemical sensor for metal ions detection with highly sensitive and selective have been explored recently. In this article, the (E)-3,3-dimethy1-24(3-oxoindolin-2-ylidene)methyl)-3H-indole-5-sulfonic acid (YYS) was designed and synthesized for detection of Cu 2+ in the presence of competing cations (Ba2+, Ag+,Na+, Fe3+, Ca2+, Co2+, Cd2+, Ni2+, Ag+, K+, Zn2+, Cr2+, Pb2+, Mg2+ Al3+) in a deionized water. An important change in color could be clearly observed by the naked eye after adding copper (II). The as-prepared colorimetric sensor has a high sensitivity with a low detection limit of 1.37 x 10(-7) M for Cu2+. "Naked eye" detection was performed, which indicated the potential application of YYS on conveniently, selectively and fast detection of Cu2+.