Cellulose-supported fluorophore as metal ion sensors

Abstract

Organic fluorescent ligands are attractive for qualitative and quantitative analysis of metal ions. Cellulose substrates, especially for filter paper, have been demonstrated as one of the most economical and easy to use platform for fluorescent sensors applied in on-site analysis with naked-eye observation. In this work, new series of amidoquinoline derivatives were synthesized and investigated as the fluorescent ligands for developing paper-based sensors. The sensors are used for convenient analysis either by simple naked-eye observation or an image processing software. In the first part of this dissertation, parallel solid-state synthesis on filter paper macroarray was used for rapid discovery and structure-property relationships of metal ion fluorescent sensors. The ligands covalently bound on the cellulose surface was used as an array of functional substrate-supported sensors which offer rapid sensing screening, reusability, and enhanced sensitivity for metal ion identification and quantitative analysis of Zn2+. The second part of the dissertation deals with a systematic modification of hydrophobicity of glycyl amidoquinoline derivatives for development of paper-based sensors having distance-based quantification capability. The distance of the fluorescent lines created in the sensor showed linear relationships with the amount of Zn2+. The linear dynamic ranges depended on the hydrophobicity of the amidoquinoline probes. The distance-based quantification of Zn2+ in drinking water, dietary supplement, and fertilizer samples by these paper-based sensors gave the results comparable with the standard method using the atomic absorption spectroscopy.