A highly selective colorimetric chemosensor for detection of iodide ions in aqueous solution

We synthesized a new iodide ion (I-) chemosensor (CS) based on a hydrazone derivative obtained from the condensation of 2-hydroxy-1-naphthaldehyde and 2,4-dinitrophenylhydrazine. The CS showed selective colorimetric recognition of I-, the miscellaneous competitive anions (F-, Cl-, Br-, HSO4-, CH3COO-, H2PO4-, SCN-, CN-, ClO4- and S-) did not lead to any significant interference. The detection limits of the CS for I- is 1.1 x 10(-6) M. The sensor has been successfully applied to estimate the content of iodide ions in urine. Moreover, ion test strips based on CS were fabricated, which could act as a convenient and efficient I- test kit for "in-the-field" measurement of iodide ions.