Light Harvesting Nanoprobe for Trace Detection of Hg2+ in Water

Abstract

The continuously increasing flow of toxic heavy metals to the environment due to intensive industrial activity and tightening requirements with regard to the content of metal ions in drinking and discharged waters urges the development of affordable and sensitive devices to the field control of pollutants. Here, we report a new thiated Rhodamine-lactam probe for Hg2+ detection and demonstrate how its sensitivity can be increased via the incorporation of the probe molecules into the optically transparent siloxane-acrylate coatings on polymethyl methacrylate and, alternatively, into the water-dispersible light-harvesting FRET nanoparticles (NPs), in which dye cations are separated by fluorinated tetraphenylborate anions. We have shown that the optimization of the FRET NPs composition had allowed it to reach the antenna effect of ~300 and fabricate “off/on” sensor for Hg2+ ion determination in aqueous solutions with the detection limit of ~100 pM, which is far below the maximum permissible concentration (MPC) of mercury in drinking water recommended by the World Health Organization. Although this work is more proof-of-concept than a ready-to-use analytical procedure, the suggested approaches to fabrication of the FRET NPs based on the popular rhodamine-lactam platform can be used as a background for the development of low-cost portable sensing devices for the extra-laboratory determination of hazardous metal ions.

Recent Progress on Fluorescent Probes in Heavy Metal Determinations for Food Safety: A Review

“…These two novel fluorescence-sensing tools were both successfully applied in the detection of Hg 2+ in seafood, which provides a new perspective for a wearable sensing apparatus. D114 and FO 511 are two other new rhodamine-lactam probes proposed for Hg 2+ detection [57,58]. D114 works well in the MeOH/H 2 O (1:1, v/v) system, with a limit of detection of 8.6 nM, and it could be contained with latex-coated slides for higher sensitivity (limit of detection as low as 0.5 nM).…”

A Laser-Printed Surface-Enhanced Photoluminescence Sensor for the Sub-Nanomolar Optical Detection of Mercury in Water

“…The probe used in the work (d114) was obtained in three successive stages from rhodamine 6 g as we described earlier [19]. 1…”

“…Thus, being an almost non-invasive analytical technique, luminescence-based sensing has become an effective analytical tool extensively used in the chemical, biomedical, and diagnostic fields due to its unique capability in terms of the sensitive monitoring of metal ions [1][2][3][4], anions [5,6], reactive oxygen species [7,8], and biomolecules [9,10]. This approach combines the benefits of real-time analysis with in situ detection [11]; however, the common solid state luminophores such as quantum dots [12,13], polymers [14,15], or organic dyes [16,17] suffer the shortcomings of low luminescence quantum efficiency and having a small extinction coefficient [18][19][20][21], which severely limits applications of these materials in the form of thin solid films for the highly sensitive detection of analytes.…”