Thus, the hydrogen ion may disturb the sensing for a target metal ion in acidic solution.For
this reason,most of these chemosensors signaled metal ions in
neutral solution system. Among them,Cu2þ-selective rhodamine
probes attracted an increasing interest because copper ions play
an important role not only in industry but in many fundamental
physiological processes,also as a widely recognized highly
noxious pollutant [21,22].