A colorimetric chemosensor based on new water-soluble PODIPY dye for Hg^2＋ detection

The phosphorus-containing PODIPY 1 as a chemosensor can detect Hg2+ by a color change from pink to violet red without the use of any instrumentation. PODIPY 1 was selective to Hg2+with a remarkable absorption change, and addition of other relevant metal ions caused almost no absorption change. The new PODIPY dye 1 was sensitive to various concentrations of Hg2+. The energy gap between the HOMO and LUMO of the metal complex 1–Hg2+is smaller than that of chemosensor 1, which is in good agreement with the red shift in the absorption observed upon treatment of 1 with Hg2+. The 1-based test strips were easily fabricated and low-cost, useful in practical and efficient Hg2+test kits.