Host Solids Containing Nanoscale Anion‐Binding Pockets and Their Use in Selective Sensing Displacement Assays

Functionalized mesoporous silica-based solids can be functionalized with e.g. guanidinium or polyol binding sites for detection of citrate and borate, respectively, in water. The solids are loaded with a dye (•; picture, left) that interacts with its binding sites. The dye is displaced by the target anions (○; right) and the corresponding anion is then detected by colorimetry.