Near‐Infrared Fluorimetric Determination of Copper(II) Ions Using CdHgTe Nanorods as Probe

Abstract

Stable water-soluble CdHgTe nanorods with an emission wavelength at 722 nm, obtained by doping Hg 2+ into CdTe nanorods, has been used as a near-infrared region (NIR) probe to investigate their interaction with copper(II) ions. A new fluorimetric method for the determination of copper(II) ions has been developed based on the quenching effect of copper(II) ions on the emission of CdHgTe nanorods. The mechanism studies show that an effective electron transfer from nanorods to the copper(II) ions occurred based on the coordination reaction between copper(II) ions and the carboxyl groups on the nanorods surface, which could be responsible for the emission quenching of CdHgTe nanorods. Under optimum conditions, the linear range of the calibration curve for the determination of Cu 2＋ is from 8.0×10-9 to 1.0×10 -6 mol/L and the detection limit is 2.0×10 -9 mol/L. Owing to low background interference of NIR measurement, the proposed method displays relative high sensitivity and selectivity. Especially, some physiologically important cations almost do not interfere with the determination of Cu 2＋ . The proposed method was also applied to the determination of trace Cu 2＋ in real aqueous samples with satisfactory results.

Ratiometric fluorescent paper sensor utilizing hybrid carbon dots–quantum dots for the visual determination of copper ions

“…However, if the pH value is above 7.4, the fluorescence quenching effect gradually declines due to the formation of the precipitated Cu(OH) 2 . 8,34,36,37 So, we chose HEPES buffer at pH = 7.4 as the suitable media for the detection of Cu 2+ . To evaluate the selectivity of the ratiometric fluorescence probe for Cu 2+ , the fluorescence intensity ratio (I 437 /I 654 ) (Fig.…”

Recent advances in II–VI group semiconductor- and carbon-based quantum dots for fluorescence-based sensing of metal ions in water

“…106,108,109 Besides fluorescent QDs, fluorescent nanorods such as Cys and TGA co-capped stable water-soluble CdHgTe nanorods demonstrated high sensitivity towards Cu 2+ ions. 110…”

Metal ions optical sensing by semiconductor quantum dots

“…65 Stable water-soluble nearinfrared-emitting CdHgTe nanorods (Cys and TGA co-capped) were used as a near-infrared (NIR) probe for Cu 2+ with a detection limit of 2.0 nM. 44 A bre-optic sensor for Cu 2+ ions, based on CdSe/ZnS QDs encapsulated within a silica shell and immobilized on the tip of an optical ber by a polyvinyl alcohol (PVA) polymer coating was proposed by Sung et al 53 The PL of diethyldithiocarbamate (DDTC) capped core-shell CdSe/CdS QDs was effectively quenched aer coordinated with Cu 2+ , and the electron transfer from excited QDs to the bound Cu 2+ was the primary mechanism for uorescence quenching (Fig. 2A).…”