Fluorescent Probes for Silver Detection Employing Phthalocyanines in Polymer Matrices

Abstract

This work covers photocharacterization and investigation of sensing behavior of thia-bridged tetrapoly(oxyethylene)substituted zinc(II) phthalocyanine derivatives (Pc-1 and Pc-2) in the solvents and solid matrices; ethyl cellulose (EC) and polyvinyl chloride (PVC) by means of absorption and emission spectroscopy. Their long-wavelength absorption and emission bands beyond 680 nm provide much lower background signal and reduced scattering for use especially in biological media with respect to other blue or green emitting fluorophores. The immobilized phthalocyanines (Pc-1 and Pc-2) exhibited remarkable fluorescence quenching upon exposure to Ag(I) ions at pH 6.5 in the concentration range of 0.5-10 mu M and 1-10 mu M, respectively. The relative signal changes in the percentage modulation were 80% and 97% for Pc-1 and Pc-2, respectively. The responses to Ag(I) ions were evaluated in terms of the effect of pH and other cations. The response time, reversibility, limit of detection and repeatability characteristics of the sensing membranes have been also examined.