Methionine-derived Schiff base as selective fluorescent “turn-on”chemosensor for Zn2+in aqueous medium and its application in livingcells imaging

tWe describe the quantitative synthesis of a Schiff base derived from methionine and salicylaldehyde(SMSB) which displayed turn-on selective fluorescent chemo-sensing properties for Zn2+in bufferedCH3CN/H2O (1:1) solution. In physiological pH (7.2 buffered) SMSB exhibited high selectivity and sen-sitivity toward Zn2+over the other selected metal ions. Upon the addition of Zn2+33 folds of emissionenhancement was observed in SMSB and limit of detection (CL) for Zn2+was found to be 5.0 × 10−7M. Thisbinding phenomenon was studied by1H NMR and HR-MS analysis. Mass spectrometry analysis revealedthat SMSB interacts with Zn2+and form a 1:1 complex, also confirmed by Job’s plot. This probe wascompletely retrieved by adding EDTANa2solution, exhibited a fluorescent quenching effect by removingZn2+from the sensor. SMSB was observed to have a good tolerance for fluorescence detection of Zn2+in pH range 6–10. Furthermore it is successfully investigated for living cells imaging using MCF-7 cells.Combine experimental results indicated SMSB to be a useful and powerful chemosensing probe for Zn2+in water as well as in living cells.