An aqueous friendly chemosensor derived from vitamin B6 cofactor for colorimetric sensing of Cu2 + and fluorescent turn-off sensing of Fe3 +

Chemosensor L derived from vitamin B₆ cofactor pyridoxal-5-phosphate was investigated for the selective detection of Cu^{2 +} and Fe^{3 +} in aqueous medium. Sensor L formed a 1:1 complex with Cu^{2 +} and displays a perceptible color change from colorless to yellow brown with the appearance of a new charge transfer band at 450 nm. In contrast, the fluorescence of L was quenched selectively in the presence of Fe^{3 +} without any interference from other metal ions including Cu^{2 +}.