Colorimetric and Naked Eye Detection of Hg۲+ in Aqueous Solutions

A chemosensor based on diazenylphenyl-۱,۳,۴-oxadiazole-۲-thiol (receptor R) was reported for the simultaneous detection of the two most toxic heavy metals, Hg۲+ and Cd۲+, in aqueous solutions. Receptor R showed high selectivity towards Hg۲+ by changing the color of a solution containing R in DMSO/water from pine frost color to gold color by the addition of Hg۲+. While other relevant metals, such as Li+, Na+, K+, Cs+, Mg۲+, Ca۲+, Al۳+, Ag+, Cu۲+, Pb۲+, Ni۲+, Cd۲+, Zn۲+, Cr۳+, Pb۴+, Hg۲+, and Mn۲+ did not affect the color of the R. However, Cd۲+ exhibited no change in the color of R, the color of a solution containing R+Hg۲+ was changed from gold yellow to crimson red by addition of Cd۲+, providing an approach for the detection of Hg۲+ and Cd۲+, simultaneously. Fluorescent studies revealed that the only Hg۲+ led to turn-on emission, which was also used for the determination of Hg۲+ in aqueous solutions.

Keywords:

Chemosensor , Heavy Metal Ion , Detection Mercury