Search

A dual signaling reaction-based probe derived from a hybrid coumarin-benzopyrylium dye was developed for Hg2+ signaling. The probe exhibited selective colorimetric Hg2+ signaling via the Hg2+-induced thiosemicarbazide-oxadiazole transformation. Interference from Cu2+ ions was successfully circumvented using a citrate buffer as a masking agent. The detection limit for Hg2+ ions was found to be 1.88 × 10–7 M. Practical application to Hg2+ detection in simulated wastewater was realized using a typical smartphone as a stand-alone data capture and data processing device.

A novel Ag + -selective reaction-based probe based on an acetylthiourea derivative of 2-(2-hydroxyphenyl)benzothiazole dye was investigated. The designed probe showed pronounced off-on type fluorescence signaling behavior towards Ag + ions via Ag + -induced desulfurization of acetylthiourea to acetylurea. The signaling was superior to the analogous thioamide-to-amide conversion in terms of both speed and signaling contrast. Interference from thiophilic Hg 2+ ions was effectively suppressed using the chelating agent EDTA as a masking agent. The practical application of the system to the detection of Ag + in simulated wastewater with a detection limit of 0.76 μM using a smartphone as an easy-to-use data capturing and processing device was successfully demonstrated.

We herein report the development of a simple structured reaction-based probe for the fluorescence signaling of Hg 2+ ions using a dithiane derivative of an excited-state intramolecular proton transfer (ESIPT) dye. The designed probe exhibited prominent fluorescence signaling behavior towards Hg 2+ ions by the deprotection of its dithiane function to an aldehyde in an aqueous acetonitrile solution. The interfering response of Cu 2+ ions was efficiently removed using citrate as both a masking agent and a buffer. Thus, the use of a citrate buffer allowed exclusive Hg 2+ -selective signaling to be obtained in the presence of common environmentally relevant transition metal ions. Signaling of the Hg 2+ ions was complete within 15 min after sample preparation, and a detection limit of 2.0 × 10 −7 M was estimated. As a practical application of the designed probe, the detection of Hg 2+ ions in simulated wastewater was tested using a smartphone as a portable signal-capturing device.