A fluorescent sensor with a detection level of pM for Cd(2+) and nM for Cu(2+) based on different mechanisms.

A fluorescent sensor L, which showed turn-on response towards Cd(2+) with a detection limit of 1.9 × 10(-12) mol L(-1) in acetonitrile-H2O buffer solution based on the PET process and turn-off response toward Cu(2+) with a detection limit of 4.9 × 10(-9) mol L(-1) in pure water at pH 3.5 based on electrostatic effects, was developed.