Development of a fluorescent chemosensor for chloride ion detection in sweat using Ag+-benzimidazole complexes

Abstract The level of chloride ions (Cl⁻) in sweat is a recognized biomarker for the genetic disorder cystic fibrosis (CF). The accurate quantitation of chloride ions in sweat is therefore a vital diagnostic tool for this life-threatening disease. In this work, a fluorescent, chloride ion chemosensor was developed by exploiting the strong interaction between silver (Ag+) and chloride ions. Using the concept of ligand displacement, six Ag+-benzimidazole complexes were prepared as candidate chloride ion chemosensors. The Ag+-2-(Furan-2-yl)-1H-benzo[d]imidazole (Ag+-FBI) complex was identified as the optimal sensor owing to its Ag+-FBI high sensitivity (limit of detection = 19 μM), short response time (