Total design of novel fluorescent probes and kinetically integrated chemical systems for the separation and detection of metal ions

Abstract

The total design of novel metal fluorescent probes for capillary electrophoresis-laser-induced fluorescence detection (CE-LIF), and along with a systematic study for high resolution by combination of various chemical parameters, including fluorometric properties, thermodynamics, and kinetics, were conducted. In these studies, sub-ppt sensitivity levels, high resolution among metal probe complexes, and robust applications to real samples were successfully obtained. In probe design, the quenching effect by heavy and paramagnetic metal ions was effectively controlled by adjusting the distance between the fluorophore and chelating moiety. Chelating moieties suitable to yield kinetic inertness were investigated amongst acyclic or macrocyclic hexa- or octadentates. In addition to the probe design, two new separation modes were developed, including: (i) a dynamic ternary complexing separation mode, in which the charge of an inert mother metal-probe complex is controlled by adding auxiliary ligands to form a ternary complex; (ii) an ion association complex separation mode, in which the addition of a polycation gives different sizes or shapes of polycation-probe association complexes, which, in turn, lead to different mobilities. Furthermore, a chemical suppression technique of metal-ion contaminants was developed, since the problem of contamination is of great importance for ultratrace detection. The contamination suppression system was achieved by integrating kinetics, and thermodynamics of the probe and the suppression reagent complexes with metal ions. This system successfully provided a contamination-free and -stable system for ppt level detection. © 2011 The Japan Society for Analytical Chemistry.