Application of Heterocyclic Polymers in the Ratiometric Spectrophotometric Determination of Fluoride

Herein we report the use of heterocyclic functional polymers in the ratiometric spectrophotometric determination of fluoride (F–). Polymers incorporating benzo[d][1,2,3]triazole moieties linked to the polymer backbone via urea links are demonstrated to have utility for the ratiometric detection of the F– ion, with a detection limit in the order of ∼2 μM. The hydrogen-bonding recognition between the benzo[d][1,2,3]triazole moiety and F– ion was investigated using UV–vis spectrophotometry and NMR analysis. The importance of the urea linkage was elucidated by investigating a second benzo[d][1,2,3]triazole functional monomer wherein the heterocyclic group is attached to the polymerizable group via a carbamate linkage. The replacement of the urea link with a carbamate group led to significantly reduced F– sensitivity. Moreover, by examining an analogous benzo[d]imidazole monomer it was demonstrated that having a nitrogen atom in the 2-position of the heterocycle was important for maximizing the sensitivity of ...