A New Use for an Old Molecule: An Anthraquinone-Based Colorimetric Chemosensor for Sensing of Citrate Anion

A reported chromogenic sensor 1 towards various di- and tri-carboxylate anions was investigated. The sensor 1 undergoes distinct color change with citrate ion (5 x 10(-3) M) from blue to green in DMSO/H2O (4:1, v/v). Moreover, citrate induced color changes were not interfered even in the presence of large excess of malate, tartrate, oxalate, malonate, succinate, glutarate, adipate, pimelate, suberate, cis-aconitate, trans-aconitate and 1,3,5-benzenetricarboxylate. The detection limit for the determination of citrate ion (0.23 +/- 0.04 mu M) of 1 in aqueous solution was also reported. Thus, the receptor 1 can be used as a colorimetric chemosensor for the determination of citrate ion.