Cross-reactive Fluroescent Indicators for Analysis of Metal-ion Mixtures

摘要

The conventional approach to optical sensing of metal ions has been to use metal-bionding indicators containing seelctive binding sites linked to a chromogenic or fluorescent tag. The one analyte-one sensor approach tends to be tedious and time consuming, especially where multiple ions need tob e determined. Most metallofluorescent indicators lack sufficient binding discrimination between metal ions to be effective for analysis of mixtures. In this paper we present an approach which exploits the cross-reactivity of semi-selective metallofluorescent indicators, combiend with multivariate analysis, to model a binding pattern for multiple metal ions. Mixtures of metal ions have different cross reactive bindign patterns with each metallofluorescent indicator. A pattern recognition algorithm capable of modeling these bindign patterns allows concentrations of individual metal ions to be determined. The fluorescence responses of the indicators and formation of the metal complexes are pH dependent, therefore calibration was performed at different pH values in the 4-9 pH range. The application of these semi-selective indicators to the development of optical array sensors for continuous, on-site monitoring in multicomponent media is discussed as a useful alternative to the one analyte-one sensor paradigm.