Microenviromental investigation of polymer-bound fluorescent chelator by fluorescence microscopy and optical spectroscopy

8-Hydroxyquinoline-5-sulfonic acid (HQS) was immobilized onto a strong-base anion-exchange resin AG MP-1 for the purpose of microenvironment investiga tion, resin characterization, and possibly sensing cadmium. The maximum loa ding of HQS was found to be 0.9340 mmol/g of AG MP-1. A plateau for Cd comp lex capacity was already obtained for 0.5500 mmol of HQS/g of AG MP-1. A mi nicolumn experiment showed an influence of influent Cd concentration on col umn capacity. IR and Raman spectra proved an electrostatic mode for HQS imm obilization and Cd complex formation. UV spectroscopy showed significant di fferences between solution and solid state for both HQS and Cd complex. A f luorescence microscopy technique was used for fluorescence spectral measure ment, microdistribution imaging, and study of photobleaching of HQS and the HQS-Cd complex in the resin phase. The fluorescence of immobilzied HQS was found to be red-shifted with regard to the solid-state HQS. The microdistr ibution of uncomplexed and Cd-complexed AG TMP-1-HQS was directly visualize d by fluorescence imaging, showing a nonuniform distribution. Cadmium compl exation modifies the fluorescence emission of uncomplexed AG MP-1-HQS, exhi biting an increased and red-shifted emission. Significant photobleaching of the fluorescence from the Cd complex was recorded, indicating the occurren ce of photochemical reactions within the microenvironment of the resin phas e.