colorimetric and naked eye detection of hg2+ in aqueous solutions

colorimetric and naked eye detection of hg²⁺ in aqueous solutions

a chemosensor based on diazenylphenyl-1,3,4-oxadiazole-2-thiol (receptor r) was reported for the simultaneous detection of the two most toxic heavy metals, hg²⁺ and cd²⁺, in aqueous solutions. receptor r showed high selectivity towards hg²⁺ by changing the color of a solution containing r in dmso/water from pine frost color to gold color by the addition of hg²⁺. while other relevant metals, such as li⁺, na⁺, k⁺, cs⁺, mg²⁺, ca²⁺, al³⁺, ag⁺, cu²⁺, pb²⁺, ni²⁺, cd²⁺, zn²⁺, cr³⁺, pb⁴⁺, hg²⁺, and mn²⁺ did not affect the color of the r. however, cd²⁺ exhibited no change in the color of r, the color of a solution containing r+hg²⁺ was changed from gold yellow to crimson red by addition of cd²⁺, providing an approach for the detection of hg²⁺ and cd²⁺, simultaneously. fluorescent studies revealed that the only hg²⁺ led to turn-on emission, which was also used for the determination of hg²⁺ in aqueous solutions.