Ratiometry, Wavelength, and Intensity: Triple Signal Readout for Colorimetric Sensing of Mercury Ions by Plasmonic Cu_2-xSe Nanoparticles

Abstract

In this study, we have reported a new colorimetric platform for sensitive and selective sensing of Hg2+ using near-infrared (NIR) plasmonic Cu2‑x Se nanoparticles (NPs) as reporters. Because of ultrahigh affinity between Hg2+ and Se2–, the added Hg2+ can react with Cu2‑x Se NPs and exchange their Cu+/Cu2+, yielding a HgSe layer around the host NPs. Accordingly, the absorption profiles of the Cu2‑x Se NPs are modulated substantially: The absorbance at 400–600 nm is increased, and the NIR localized surface plasmon resonance dramatically decreases with a more than 150 nm bathochromic shift. Thus, the system possesses triple signal responses, namely, ratiometry, wavelength, and intensity, to the analytes simultaneously. Such uniquely multiple signal output not only provides more choices for the quantification, but also enhances the reliability in the analyte detection. By rationally choosing poly­(allylamine hydrochloride) as the NP template, Hg2+ ions can be determined as ranging from 0–800 nM. The detection limit is as low as 2.7 nM, which is nearly 4 times lower than the limit value (10 nM) defined by the U.S. Environmental Protection Agency for drinking water. Other heavy/transition metal ions, such as Cu2+, Ag+, Pb2+, Cd2+, Ni2+, Co2+, Mn2+, Zn2+, Cr3+, Fe2+, and FeF6 3–, do not interfere with the sensing. Especially, Hg2+ contents can be quantified, even if their concentrations are as low 10 nM in tap water and common environmental water samples. Due to favorable analytical performance, the proposed Cu2‑x Se NPs based system has potential applications in monitoring trace Hg2+ in various real samples, even in drinking water.

Plasmonic doped semiconductor nanocrystals: Properties, fabrication, applications and perspectives

“…The films (Figure 28). [255] The interesting part of these approaches to sensing is that the sensitivity is based on real chemical reactions, differently from the refractive-index based probing exploited in noble metal nanoparticle sensors.…”

“…The affinity of copper chalcogenide NC to uptake metal cations has been proposed as a way to extract heavy metals from solution [32,255]. The resulting LSPR shifts and the changes in optical properties were proposed as an associated sensing tool.…”

“…The released Cu species are mostly recaptured by the not exchanged CuS domains or by the remaining CuS NCs leading to the LSPR quenching. [32] Along similar lines, Zhang et al[255] have reported a new colorimetric platform for sensitive and selective sensing of Hg 2+ by using NIR plasmonic Cu 2-x Se NCs which exploits the strong tendency of Hg 2+ to exchange the copper cations inCu 2-x Se NCs, yielding a HgSe layer around the host NCs. The absorbance in the visible is thereby red shifting, with a simultaneous dramatic decrease of the NIR plasmon resonance.…”

Chemical Degradation of Mercury Alkyls Mediated by Copper Selenide Nanosheets

“…In this context, copper selenides have attracted considerable interest due to their diverse applications, well‐documented synthetic procedure of various types, namely stoichiometric (CuSe, CuSe 2 ) and nonstoichiometric (Cu 2− x Se) phases, and also consider as the common selenium minerals . Recently, Cu 2− x Se nanoparticle is used as a colorimetric platform for selective sensing of Hg 2+ in drinking water . Herein, we report for the first time the Hg−C bond cleavage of various mercury alkyls including highly inert MeHgCl and Me 2 Hg mediated by CuSe nanomaterials at room temperature (21 °C).…”

“…[12] Recently,C u 2Àx Se nanoparticle is used as ac olorimetric platform for selective sensing of Hg 2 + in drink-ing water. [13] Herein,w er eport for the first time the HgÀC bond cleavage of various mercury alkylsi ncluding highly inert MeHgCl and Me 2 Hg mediated by CuSe nanomaterials at room temperature (21 8C).…”