Determination of Fe2+ and Co2+ by a Multiple-Target Colorimetric Chemosensor with Low Detection Limit in Aqueous Solution

A highly effective colorimetric chemosensor DPKP, N '-(di(pyridin-2-yl)methylene)-6-hydroxypicolinohydrazide, was synthesized. DPKP sensed Fe2+ and Co2+ with the changes of color from colorless to blue and yellow, respectively, without severe inhibition from other metal ions. Binding interactions of DPKP with Fe2+ and Co2+ were analyzed to be 1:1 and 2:1 with Job plot and ESI-MS analyses, respectively. In particular, DPKP has low detection limits for Fe2+ (0.60 mu M) and for Co2+ (0.22 mu M). In addition, DPKP could be used for quantification of Fe2+ and Co2+ in environmental samples.