An organically modified sol–gel membrane for detection of lead ion by using 2-hydroxy-1-naphthaldehydene-8-aminoquinoline as fluorescence probe

A fluorescent reagent, 2-hydroxy-1-naphthaldehydene-8-aminoquinoline (HNAAQ) was synthesized, and an organically modified sol–gel membrane for detection of lead ion by using HNAAQ as fluorescence probe was fabricated. Under the optimum conditions, by a coplanar effect and the degree of molecular conjugation due to the complexation of Pb2+ with HNAAQ the relative fluorescence intensity I100/I0 of the sensing membrane is linearly increased over the Pb2+ concentration range of 1.9 × 10−7 to 1.9 × 10−4 mol/L with the detection limit of 8.3 × 10−8 mol/L. The preparation of this organically modified sol–gel membrane and its characteristics were investigated in detail.