Water-Soluble Polymeric Probes for the Selective Sensing of Mercury Ion: pH-Driven Controllable Detection Sensitivity and Time

Abstract

Polymeric probes with dithioacetal units in the side chains were designed and synthesized for the selective and efficient colorimetric sensing of Hg2+ ions in aqueous solutions. These polymeric sensors were prepared by a reaction between aldehyde groups of the side chain in the polymer and ethanethiol or 3-mercaptopropionic acid using BF3 as a Lewis acid. In aqueous solution, they exhibited a 30–40 nm red-shift in their absorption maxima upon the addition of Hg2+ ions, accompanied by a change in the color of the solution, from pale yellow to dark red. These results clearly demonstrated that the sensitive signaling behaviors originated from the Hg2+-promoted deprotection reaction of dithioacetal groups to form aldehyde functionalities. The sensors have excellent selectivity toward Hg2+ ions over other alkali and transition metal ions. The detection time for Hg2+ ion was finely tuned by a change in the pH of the solution. In particular, it took less than 1 min to complete Hg2+ ion detection at low pH. Given with fast and pH-tunable Hg2+ ion detection abilities, these polymeric probes are expected to offer unique potential platforms for integrating stimuli-responsive water-soluble polymers with tunable sensing behaviors.

Colorimetric and fluorometric probes for the optical detection of environmental Hg(ii) and As(iii) ions

“…Another stimuli-responsive polymeric sensors 76a and 76b were developed for the detection of Hg 2+ colorimetric way with pH-tunable sensitivity. [138] The sensor 76a was developed by the protection of the aldehyde group of azo-polymer with ethanethiol and 76b…”

Recent Progress in Functional Materials for Selective Detection and Removal of Mercury(II) Ions

“…Reproduced with permission. [ 12a ] Copyright 2015, American Chemical Society. E) Schematic illustration of the recyclable DNA‐derived polymeric system for ultrasensitive detection of Hg 2+ .…”

“…In 2015, Lee and his co‐worker introduced an efficient and selective polymeric probes bearing dithioacetal moieties in the side chains to detect Hg 2+ in aqueous solutions. [ 12a ] Polymer 2 with ethyl moieties and Polymer 3 with carboxyl moieties in the side chains were synthesized through the reaction between aldehyde moieties of Polymer 1 and ethanethiol/3‐mercaptopropionic in the presence of BF 3 (Figure 7C). Upon the addition of Hg 2+ into the polymeric system of Polymer 2 and Polymer 3, the redshift (from 425 to 458 nm and from 428 to 458 nm, respectively) of the absorption peak of the two systems appeared owing to intramolecular charge transfer (ICT), accompanied with the color change from pale yellow to dark red.…”

“…[ 7i,11 ] Undoubtedly, enormous polymeric probes including pH‐responsive and thermal‐responsive systems have superiorities of prominent recyclability, low cost, and green detection for the application in real samples. [ 12 ] Third, novel applicable probes with aggregation‐induced emission (AIE)‐active characteristics also play a crucial part in selective detection and thorough removal of harmful pollutants. On the contrary to aggregation‐caused quenching (ACQ) systems, [ 13 ] the fluorescent probes bearing AIE properties are nearly nonemissive in dilute solution, but turn strongly emissive in the aggregate states, which were first reported by Tang and co‐workers.…”

Carbon Dioxide‐Controlled Assembly of Water‐Soluble Conjugated Polymers Catalyzed by Carbonic Anhydrase

“…In recent years, WCPs have been developed as ideal platforms for the biological applications such as high sensitivity sensing and detection, as well as cell imaging, disease diagnosis, and drug delivery . In most cases, these WCPs‐based biological applications take advantages of their responsive properties to the external signals including pH value, electrical charge, and ligands by changing their photophysical property, assembly, and conformation. Recently, Yoon and colleagues developed polydiacetylene‐based CO 2 detection system by applying the response of conjugated polymer to CO 2 in aqueous solution and in the solid state.…”