A fluorescence turn-on Hg<sup>2+</sup> probe based on rhodamine with excellent sensitivity and selectivity in living cells

A highly sensitive and selective Hg2+ probe 4 based on rhodamine-b was developed and characterized. In consideration of environmental and biological application, we connected a water soluble receptor group (sulfonated β-naphtol) and rhodamine-b together through hydrazine hydrate in high yield. The result turns out that this compound not only exhibits excellent sensitivity and selectivity toward Hg2+, but also shows well cell permeability and compatibility in vitro.