Convenient and highly effective fluorescence sensing for Hg2+ in aqueous solution and thin film.

A quinolinocyclodextrin, that is, MQAS-beta-cyclodextrin (MQAS = N-(2-methyl-8-amino- quinolyl)-p-aminobenzene sulfonamide) was synthesized. Further experiments showed that it could form very stable stoichiometric 2:1 complex with Zn(2+) in water. Significantly, the resultant quinolinocyclodextrin/Zn(2+) complex showed the specific fluorescence response to Hg(2+) over other metal ions, which could be readily distinguished in either aqueous solution or the PVA-based thin film. This finding would enable Zn x 3(2) complex as a convenient and highly efficient fluorescence sensor for the detection of Hg(2+).