Preparation of β-Cyclodextrin Encapsulated Squaramide Based Chemosensor for the Selective Detection of I^- and NO₂^-

A β-cyclodextrin encapsulated squaramide derivative SA (cyclobutab quinoxaline-1,2 (3H, 8H)-dione) were synthesized for the selective sensing of I^- and NO₂^- in aqueous solution in competitive fashion. With I^- and NO₂^-, the encapsulated probe shows a highly characteristic UV-Vis absorbance enhancement at centered 262 and 365 nm, respectively over other tested ions. Furthermore, the quantitative analysis of the both target anions was successfully achieved by the absorption titration, making the fast and trace amount detection of I^- and NO₂^- possible by probe.