Rhodamine-labeled Sensor Bead as a Colorimetric and Fluorometric Dual Assay for Hg2+ Ions in Water

Rhodamine-based receptor 1 recognizes Hg2+ and Cu2+ ions in aqueous CH3CN, but when immobilized onto Merrifield resin to give bead 2, this sensor system selectively detects Hg2+ ions over a series of other metal cations in water. The detection can be performed colorimetrically and fluorimetrically. The ensemble of 2-Hg2+ can also distinguish DL-homocysteine from L-cysteine in water by both analytical methods.