A highly sensitive and selective bissalamo-coumarin-based fluorescent chemical sensor for Cr3+/Al3+ recognition and continuous recognition S2-

A bissalamo-coumarin-based chemical sensor H4L was designed and synthesized. It was found that the sensor molecule can selectively recognize Cr3+ and Al3+. In a buffer solution system, its complex L - Cr3+ is highly sensitive to the detection of S2- anion, and the sensor H4L can recognize Cr3+ at an acceptable physiological pH. Within the range, L - Cr3+ can recognize S2- anions with high selectivity and sensitivity. The detection limit for the sensor molecule H4L to recognize Cr3+ is 4.87 x 10(-7) M, and the quenching constant with Cr3+ is 2.406 x 10(6) M-1. It was calculated that the detection limit of L - Cr3+ as a sensor was 8.23 x 10(-7) M, and the binding constant with S2- anion was 1.44 x 10(6) M-1. The possible recognition mechanisms were discussed by UV, fluorescence titration, ESI-mass spectrometry and Job curve. In addition, S2- in different water samples was detected and the recovery was good.

Automated summary

A bissalamo-coumarin-based chemical sensor H4L was designed and synthesized, which selectively recognizes Cr3+ and Al3+. The complex L - Cr3+ is highly sensitive to the detection of S2- anion, with high selectivity and sensitivity. Detection limits and binding constants with Cr3+ and S2- were calculated, and possible recognition mechanisms were discussed, showing good recovery in detecting S2- in different water samples.