RETRACTED: l-Cysteine-capped ZnS quantum dots based fluorescence sensor for Cu2+ ion

Koneswaran, Masilamany; Narayanaswamy, Ramaier

doi:10.1016/j.snb.2008.09.028

Cited by 292 publications

(119 citation statements)

References 26 publications

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“…One of QDs' applications in biosensing methods is fluorescence quenching. As already reported, in aqueous solutions, the fluorescence intensity of QDs could be effectively quenched by heavy metal ions like Pb 2+ [27], Cu 2+ [28][29][30], or free radicals [31,32]. Our preliminary tests indicated that several components or contaminants contained in used oils, such as heavy metal ions, free radicals, electron withdrawing groups, and conjugated carbon-carbon double bonds, could also quench the fluorescence of QDs.…”

Section: Introductionsupporting

confidence: 77%

“…The interdigitated bilayer structure of CTAB-TOPO-coated CdSe/ZnS QD, whose first layer was original surface ligands TOPO and the second layer was CTAB, made it a more sensitive and selective fluorescence probe than CdSe/ZnS QD to the quenchers [46]. Similar organic coated bilayer structures of water-soluble CdSe/ZnS QDs were also investigated by others as fluorescence quenching probes for selective detection and quantification of analytes like chloride anion [47], hypochlorite [48], heavy metal ions [27][28][29][30]49], nitroaromatic [50] and even chiral mixtures of enantiomers [51,52].…”

Section: Comparison Of Oil-soluble Qds and Water-soluble Ctab-coated Qdsmentioning

confidence: 99%

“…Used oils that had contacted with metal ware when they were heated for frying food and held for storage and transportation, were severely contaminated by heavy metal ions, such as Pb 2+ , Cr 6+ , Cu 2+ , Mn 2+ , Zn 2+ , Ni 2+ [54]. The Pb 2+ [27] and Cu 2+ [28][29][30] were demonstrated to decrease the fluorescence intensity of functional ligands capped CdSe/ZnS QDs. One mechanism of the fluorescence quenching of surface modified inorganic CdSe/ZnS QDs was the cation exchange of Zn with the quenching heavy metals.…”

Section: Comparison Of Oil-soluble Qds and Water-soluble Ctab-coated Qdsmentioning

confidence: 99%

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Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Xiong

et al. 2014

Sensors and Actuators B: Chemical

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a b s t r a c tVegetable cooking oils adulterated with inedible used oils or impure oils have posed a severe food safety problem. Current detection methods cannot meet the needs for rapid detection of adulterated oils on line or in field. Therefore, the objective of this research was to develop a rapid optical sensing method based on fluorescence quenching of CdSe/ZnS quantum dots (QDs) for identification of adulterated vegetable cooking oils. High quality hydrophilic photoluminescent nanoparticles were synthesized by encapsulating hydrophobic QDs into the micellar structure of an amphiphilic surfactant cetyltrimethyl ammonium bromide (CTAB) via phase transfer method. TEM, AFM, and fluorescence spectroscopy were used to characterize the prepared CTAB-coated QDs. Oil samples were first captured into the core of the twolayer-structural micelle and then the fluorescence of CTAB-coated QDs, working as fluorescence probes, was selectively quenched by components of the adulterated oils. Heavy metal ions and free radicals were presumed to be main quenchers. After quenching for 1 min, fluorescence intensity was measured and converted to quenching percentage to determine the adulteration concentration. The results showed that in comparison with oil-soluble QDs, water-soluble CTAB-coated QDs had a greater ability to identify oil adulteration. A good quantitative relationship between quenching percentage and adulteration concentration (y = 5.96x + 14.99; R 2 = 0.94) was obtained. The sensitive, simple and low-cost sensing method did not require sample pretreatment and could detect refined used oils at 0.4% or higher concentrations in soybean oil within 2 min, showing great potentials for rapid screening of used oils and quantitative analysis of used oil adulteration in field.

show abstract

Section: Introductionsupporting

confidence: 77%

Section: Comparison Of Oil-soluble Qds and Water-soluble Ctab-coated Qdsmentioning

confidence: 99%

Section: Comparison Of Oil-soluble Qds and Water-soluble Ctab-coated Qdsmentioning

confidence: 99%

See 1 more Smart Citation

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Xiong

et al. 2014

Sensors and Actuators B: Chemical

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“…Narayanaswamy and co-workers reported the synthesis of L-cysteine-capped ZnS QDs and used them for Cu detection [401]. Cysteine is a water-soluble amino acid and frequently used as a capping agent for ZnS QDs.…”

Section: Zinc Sulphidementioning

confidence: 99%

Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist

2017

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Abstract:Metal sulphides, and in particular transition metal sulphide colloids, are a broad, versatile and exciting class of inorganic compounds which deserve growing interest and attention ascribable to the functional properties that many of them display. With respect to their oxide homologues, however, they are characterised by noticeably different chemical, structural and hence functional features. Their potential applications span several fields, and in many of the foreseen applications (e.g., in bioimaging and related fields), the achievement of stable colloidal suspensions of metal sulphides is highly desirable or either an unavoidable requirement to be met. To this aim, robust functionalisation strategies should be devised, which however are, with respect to metal or metal oxides colloids, much more challenging. This has to be ascribed, inter alia, also to the still limited knowledge of the sulphides surface chemistry, particularly when comparing it to the better established, though multifaceted, oxide surface chemistry. A ground-breaking endeavour in this field is hence the detailed understanding of the nature of the complex surface chemistry of transition metal sulphides, which ideally requires an integrated experimental and modelling approach. In this review, an overview of the state-of-the-art on the existing examples of functionalisation of transition metal sulphides is provided, also by focusing on selected case studies, exemplifying the manifold nature of this class of binary inorganic compounds.

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“…Traditional methods such as atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS) to detect mercury ions are often costly, timeconsuming and not appropriate for point-of-use applications [4], so there is a strong demand to develop a novel method with the advantages of the few interference, facile fabrication process, and low cost. The advantages of fluorescence signaling in its intrinsic sensitivity have encouraged the development of a variety of fluorescent sensors for the detection of metal ions [5][6][7]. As new type of fluorescent sensors, QDs offer a number of attractive features, including high photobleaching threshold, good chemical stability, relatively broad and symmetric luminescence bands [8,9], which wished to remedy the deficiencies of the fluorescent dyes.…”

Section: Introductionmentioning

confidence: 99%

Highly sensitive synchronous fluorescence determination of mercury (II) based on the denatured ovalbumin coated CdTe QDs

Wang

Liu

et al. 2012

Talanta

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RETRACTED: l-Cysteine-capped ZnS quantum dots based fluorescence sensor for Cu2+ ion

Cited by 292 publications

References 26 publications

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

Functionalisation of Colloidal Transition Metal Sulphides Nanocrystals: A Fascinating and Challenging Playground for the Chemist

Highly sensitive synchronous fluorescence determination of mercury (II) based on the denatured ovalbumin coated CdTe QDs

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