Configurable fluorescent constructs for detection and discrimination of fluoride and biological phosphates

Abstract

Designing fluorescence sensors for effective recognition and discrimination of multiple species is a challenging task. This study describes a simple and unique supramolecular strategy in which sensing of the anions fluoride and phosphate, which are generally difficult to distinguish, has been accomplished by using fluorescent ensembles formed by reversible in situ co-ordination of Al(III) with the chromophore, quinizarin (QZ), at different Al(III):QZ concentration ratios. The QZ-aluminium sensing ensemble is also found to be useful for differentiating between the biologically relevant phosphates, viz. adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP), by the application of principal component analysis. The present sensor system is advantageous because it can be readily assembled from off-the-shelf chemicals, it can operate in aqueous medium that is desirable for working under physiological conditions, and it functions in the ratiometric fluorescence mode that is useful for reducing interferences from intensity fluctuations and background fluorescence. The sensing approach described in this study can pave the way for development of multi-analyte sensor arrays from the same constituents by simply assembling them at different concentrations, instead of the conventional approach of designing separate sensors.