A new determining method of copper(II) ions at ng�ml?1 levels based on quenching of the water-soluble nanocrystals fluorescence

Abstract

CdTe nanocrystals (NCs) were prepared and modified in aqueous solution by using 3-mercaptopropionic acid (MPA). Compared with previous fluorescent sensors based on organic fluorophores, these NCs have the following merits. First, they are sensitive and the synthetic procedure is simple; second, they have narrow, tunable, symmetric emission spectra and are photochemically stable. The applicability of these NCs to the determination of Cu(II) ions was studied successfully. Maximum fluorescence intensity was produced at pH 7.8, with excitation and emission wavelengths at 365 and 532 nm, respectively. Under optimal conditions, linear relationships were found between the relative fluorescence intensity and the concentration of Cu(II) ions in the range 0-256 ng ml(-1) and the limit of detection was 0.19 ng ml(-1). This method was applied to determine real samples successfully. In addition, the quenching mechanism is also described.

A Novel Fluorescent Probe for Copper Ions Based on Polymer-modified CdSe/CdS Core/Shell Quantum Dots

“…21 Thus, the formation constant of QDs-MAO-mPEG with Cu 2+ could be calculated as 2.88 × 10 6 M -1 according to a method reported elsewhere. 22 Compared with the reported QDs analytical systems, [13][14][15][16][17][18] the difference is that our presented QDs is based on the CdSe/CdS core/shell and the QDs surface is modified by an amphiphilic polymer of MAO-mPEG. Until now, there were not very clear mechanisms for the interpretation of fluorescent quenching of QDs with heavy metal ions.…”

“…nanocrystals modified with mercaptopropionic acid were proposed for the determination of Cu(II) ions. 18 A lack of selectivity and low stability of the QDs in the aqueous media were among the problems reported for some of the procedures proposed.…”

Development of an Albumin Copper Binding (ACuB) Assay to Detect Ischemia Modified Albumin

“…27 Figure 3 shows that Cu-induced LY quenching did not fit the Stern-Volmer equation, but F0/F versus copper represented a sigmoidal curve. Copper in the amount of The mixture samples were prepared as follows: 0.1 mM tetrapeptide and 0.1 mM CoCl2 and CuCl2 were mixed in the written order with incubation for 10 min, and then the samples were analyzed.…”

The Composites of Cationic Polyelectrolyte and Glutathione‐capped Quantum Dots for Selective Fluorescence Detection of Cu2+

“…Selective fluorescence quenching of 3-mercaptopropionic acid-capped CdTe QDs has been carried out in the presence of Cu 2+ while a solution contains masking agents for Al 3+ and Hg 2+ . 24 A brightorange CdTe nanowires, which were made through self-assembly thioglycolic acid-capped CdTe QDs, have been utilized for selective detection of Cu 2+ . 25 Although these above mentioned approaches all provide high sensitivity for detection of Cu 2+ , the solution of problems associated with cross-sensitivity toward other metal ions, limitation in practical use, short dynamic range, and additional masking agents remains a challenge.…”