Highly sensitive and selective determination of copper(II) based on a dual catalytic effect and by using silicon nanoparticles as a fluorescent probe

Abstract

The authors describe a silicon nanoparticle-based fluorometric method for sensitive and selective detection of Cu. It is based on the catalytic action of Cu on the oxidation of cysteine (Cys) by oxygen to form cystine and the by-product HO. The generated HO is catalytically decomposed by Cu to generate hydroxyl radicals which oxidize and destroy the surface of SiNPs. As a result, the blue fluorescence of the SiNPs is quenched. The method has excellent selectivity due to the dual catalytic effects of Cu, which is much better than most previously reported nanomaterial-based assays for Cu. Under the optimal conditions, the method has low detection limit (29 nM) and a linear response in a concentration range from 0.05 μM to 15 μM. The method has been successfully applied to the determination of Cu in spiked real water samples, and the results agreed well with those obtained by the Chinese National Standard method (GB/T 7475-1987; AAS). Graphical abstract Schematic presentation of a fluorometric method for the determination of Cu based on the dual catalytic effects of Cu, and the oxidative effect of hydroxy radicals on the surface of silicon nanoparticles (SiNPs). The method has a 29 nM detection limit and good selectivity.

Detection of Cu(II) in water by using N, S co-doped carbon dots

“…Together with colorimetric methods also fluorometric detection is also reported for comparison. The present LOD (0.3 µM) is exceeded by those of some other colorimetric [30], [31], and also some fluorimetric ones [32], [33]. However, it is still well below the guideline limit suggested by the WHO (30 micromole).…”

Functional ZnS:Mn(II) quantum dot modified with L-cysteine and 6-mercaptonicotinic acid as a fluorometric probe for copper(II)

“…However, they also have some problems, such as a complicated synthesis [4,35] or low sensitivity [9,13,14,21,36]. Although our synthesis procedure is slightly more complex than that reported [14,19,21,22], excitingly, the detection limit is much better than that of reported methods [4,9,13,14,21,22,36]. In the research of [18], lower detection limit and wider linear rang is attained, however, the method is based on CdTe QDs (less ecofriendliness than ZnS QDs) and needs a passivation procedure.…”

“…Various fluorescence substances are available for the fluorescence detection, such as organic dyes [10][11][12], carbon dots [13,14], quantum dots (QDs) [15][16][17][18][19], silicon nanoparticles [20,21] and metal nanoclusters [22]. Single wavelength fluorescence intensity is usually used as detection value, but it can be influenced by stability of light source, solution composition and environmental factors.…”

A Quinoxaline−Naphthaldehyde Conjugate for Colorimetric Determination of Copper Ion

“…Our contribution touches upon a problem of interest in analytical chemistry, e.g., the design of selective and sensitive determination methods of copper (II) [36][37][38][39][40][41][42]. We have performed the follow-up work of quinoxaline-naphthaldehyde-based probe QNH and its selective detection of Cu 2+ in HEPES−buffer/acetonitrile (3/7, v/v) medium.…”