Specific colorimetric detection of Fe3+ ions in aqueous solution by squaraine-based chemosensor†
Abstract
A new squaraine based chemosensor TSQ was developed for colorimetric detection of Fe3+ ions. A thymine moiety in TSQ was constructed to act as an ion acceptor. The sensor displayed an instant colorimetric response specific to Fe3+ over the other metal ions in 20% AcOH–H2O solution. The limit of detection was much lower than that of the environmental protection agency guideline (5.37 μM) in drinking water. A 1 : 1 binding between TSQ and Fe3+ ion was evidenced by Job's plot measurement, ESI-MS and Fourier transform infrared (IR) measurements. Moreover, the proposed sensing mechanism of the receptor towards Fe3+ was strongly supported by DFT calculation. Finally, the sensor has proven to be suitable in real sample applications.