A New Fluorescent "Off-On" Sensor for Al(3+) Derived from L-alanine and Salicylaldehyde

The condensation product of L-alanine and salicylaldehyde was synthesised and characterised which was found to be selective fluorescent "on" sensor for Al(3+) ion with the detection limit 10(-6) M. The sensor is free of interferences from metal ions - Na(+), K(+), Ca(2+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Pb(2+), Cd(2+), Hg(2+) and Fe(3+). The Fluorescence and the UV/visible spectral data reveals a 1:1 interaction between the sensor and Al(3+) ion with binding constant 10(4.5). The DFT and TDDFT calculations confirm the structures of the sensor and the sensor-Al(3+) complex.