COLORIMETRIC “OFF-ON” PROBE FOR CU2+ NANOMOLAR DETECTION IN AQUEOUS SOLUTION

Abstract

An imine based colorimetric probe (3) was synthesized and explored it recognition properties against various metals. The
absorption spectra of (3) showed absorbance maxima at 325nm. The addition of Cu2+ in the receptor (3), changed the
absorption spectrum of receptor (3) with the appearance of a new band at ~385 nm. The association constant (Ka) of
receptor (3) with Cu2+ ions was found at 2.3 × 105 M-1 with the formation of (receptor-Cu2+) complexes in 1:1
stoichiometry. The receptor (3) (C=1×10-5 M) is yellow coloured in CH3OH/H20 (80:20, v/v) and addition of Cu2+
results into green coloured solution. The LOD was found to be 183nM from 10 blank solutions.