Functionalized cadmium sulfide quantum dots as fluorescence probe for silver ion determination

We report lead (Pb 2? ) and chromium (Cr 3? ) determination in several water samples obtained from Nahand dam, Karkaj and Azarshahr well, tab and mineral waters to study their contamination in these systems. Determination method is based on the characteristic aggregation and fluorescence quenching of synthesized CdS quantum dots (QDs) at 555 nm by considered cations. Water-soluble and biocompatible CdS QDs modified with thioglycolic acid have been synthesized in one step and characterized by fluorescence and absorption spectroscopy. The fluorescence intensity of CdS QDs is linearly proportional to Pb 2? and Cr 3? concentration from 0.8 to 100 and 3 to 400 ng mL -1 with a detection limit of 0.3 and 1.2 ng mL -1 , respectively. Other potentially interfering ions such as iron, sodium, potassium, calcium, and magnesium ions did not affect the luminescence. The method showed lower detection blank and higher sensitivity.

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“…[25][26][27][28][29], Ag ? [25,30], Pb 2? [31][32][33] based on their fluorescence quenching effect.…”

Section: Introductionmentioning

confidence: 99%

Ultrasensitive determination of lead and chromium contamination in well and dam water based on fluorescence quenching of CdS quantum dots

Abolhasani

Jalali

2014

Int Nano Lett

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“…The detection limit was 1.6 nmol L −1 . Compared with the current luminescent method 32,35,38,39 , the present method has analytical performance with satisfactory results due to higher sensitivity and wider linear range to silver ion detection ( Table 1).…”

Section: Calibration Curve and Sensitivitymentioning

confidence: 88%

“…Bismuthiol II has a complex structure with RS -and reactive functional group containing N and S donor atoms. It may adsorb on the surface of CdS particle by Langmuir adsorption 35 . The adsorption makes the surface of CdS particle passivate and improves the stability and luminescent efficiency of the particle 36,37 .…”

Section: Spectral Characteristics Of Fluorescencementioning

confidence: 99%

Determination of Silver Ion with Cadmium Sulfide Quantum Dots Modified by Bismuthiol II as Fluorescence Probe

et al. 2006

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Summary -CdS quantum dots (QDs) modified with bismuthiol II potassium salt is prepared in one step. Based on the characteristic fluorescence enhancement of CdS QDs at 480 nm by silver ions, simultaneously, a red shift of fluorescence emission bands of CdS QDs from 460 to 480 nm is observed. A simple, rapid, sensitive and specific detection method for silver ion is proposed. Under optimum conditions, the fluorescence intensity of CdS QDs was linearly proportional to silver ion concentration from 0.01 to 5.0 µmol L -1 with a detection limit of 1.6 nmol L -1 . In comparison with single organic fluorophores, functionalized CdS quantum dots are brighter, more stable against photobleaching and do not suffer from blinking. Furthermore, the proposed method shows higher sensitivity and selectivity. A possible fluorescence enhancement mechanism is also studied.

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“…The slope (sensitivity) of H 2 O 2 determination was maximal with a volume ratio of CdS:CS of 1 : 1. Obviously, the selectivity of the composite film was reduced at higher contents of CdS QDs because CdS QDs can interact with several ions in the supporting electrolyte and interfere with the reaction between Hb and H 2 O 2 [22]. At high contents of CS, the composite film was easily swollen with lower surface adhesion because of the hydrophilic property of CS [21].…”

Section: Cadmium Sulfide Quantum Dots and Cds/cs Composite Characterimentioning

confidence: 95%

A Highly Sensitive Hydrogen Peroxide Biosensor Based on Hemoglobin Immobilized on Cadmium Sulfide Quantum Dots/Chitosan Composite Modified Glassy Carbon Electrode

et al. 2014

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An L‐cysteine capped cadmium sulfide‐chitosan nanocomposite has been synthesized, characterized and used for surface modification of a glassy carbon electrode. With direct electron transfer, hemoglobin (Hb) adsorbed strongly on the nanocomposite and displayed excellent bioelectrocatalysis for H2O2. The biosensor was capable of reducing H2O2 at −0.35 V, with a detection limit of 3.13 nM, linearity in the range of 15 nM to 10 µM and a response time of less than 2 s. The MichaelisMenten constant (KM) was 0.57 nM, attesting high bioelectrocatalysis of immobilized Hb for H2O2. Reproducibility of the fabrication method was very satisfactory with a relative standard deviation of 5.3 %. The biosensor lost only 6.5 % of its original response after 7 days when stored in a pH 7.4 PBS at 4 °C.

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Functionalized cadmium sulfide quantum dots as fluorescence probe for silver ion determination

Cited by 179 publications

References 28 publications

Ultrasensitive determination of lead and chromium contamination in well and dam water based on fluorescence quenching of CdS quantum dots

Ultrasensitive determination of lead and chromium contamination in well and dam water based on fluorescence quenching of CdS quantum dots

Determination of Silver Ion with Cadmium Sulfide Quantum Dots Modified by Bismuthiol II as Fluorescence Probe

A Highly Sensitive Hydrogen Peroxide Biosensor Based on Hemoglobin Immobilized on Cadmium Sulfide Quantum Dots/Chitosan Composite Modified Glassy Carbon Electrode

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