A multi-functional picolinohydrazide-based chemosensor for colorimetric detection of iron and dual responsive detection of hypochlorite.

A novel effective chemosensor HPHN, (E)-6-hydroxy-N'-((2-hydroxynaphthalen-1-yl)methylene) picolinohydrazide, was synthesized. HPHN sensed Fe with the changes of color from yellow to orange without obvious inhibition from other cations. In addition, HPHN could detect ClO by both the color change from yellow to colorless and the fluorescence quenching. The binding modes of HPHN with Fe and ClO were determined to be 1:1 with Job plot and ESI-mass analysis. HPHN displayed low detection limits of 0.29 μM for Fe and 0.77 μM for Fe. For ClO, the detection limit was 6.20 μM by colorimetric method and 3.99 μM by fluorescent one, respectively. Moreover, HPHN can be employed to quantify Fe and ClO in environmental samples and apply to cell imaging for ClO.