A CdTe/CdS/ZnS core/shell/shell QDs-based “OFF–ON” fluorescent biosensor for sensitive and specific determination ofl-ascorbic acid
- 5 September 2014
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in RSC Advances
- Vol. 4 (87), 46751-46761
- https://doi.org/10.1039/c4ra08169b
Abstract
Herein we report a quantum dots (QDs)-based “OFF–ON” fluorescent biosensor for the sensitive and specific determination of L-ascorbic acid. The proposed one-pot L-ascorbic acid detection method is quite simple, rapid and convenient because of the elimination of the modification and separation procedures. In this contribution, the N-acetyl-L-cysteine (NAC)-capped CdTe/CdS/ZnS core/shell/shell QDs were synthesized in aqueous phase. Subsequently, KMnO4 was added into solution and attached to the QDs surface to effectively quench the fluorescence of the QDs, which rendered the QDs into fluorescence “OFF” status. After the addition of L-ascorbic acid into the QDs–KMnO4 system, the fluorescence of the QDs was then turned “ON” because L-ascorbic acid could bind with KMnO4 and break KMnO4 away from the surface of the QDs. Under the optimized conditions, the relative restored fluorescence intensity was directly proportional to the concentration of L-ascorbic acid in the range of 8.0 × 10−9 M to 1.0 × 10−7 M, with a correlation coefficient of 0.9971 and a limit of detection of 1.8 × 10−9 M. The relative standard deviation for 6.0 × 10−8 M L-ascorbic acid was 2.1% (n = 5). There was almost no interference from few common ions, carbohydrates, nucleotides and amino acids. The proposed method was applied to the determination of L-ascorbic acid in three synthetic samples, human urine samples and vitamin C tablets with satisfactory results. The possible fluorescence quenching mechanism of this fluorescent sensor was further investigated by UV-vis spectroscopy.Keywords
Funding Information
- National Natural Science Foundation of China (21203035)
This publication has 46 references indexed in Scilit:
- A novel surface modification strategy of CdTe/CdS QDs and its application for sensitive detection of ct-DNASensors and Actuators B: Chemical, 2014
- Fluorescence enhancement detection of uric acid based on water-soluble 3-mercaptopropionic acid-capped core/shell ZnS:Cu/ZnSRSC Advances, 2014
- Facile synthesis of chitosan-capped ZnS quantum dots as an eco-friendly fluorescence sensor for rapid determination of bisphenol A in water and plastic samplesRSC Advances, 2014
- Allergen immobilisation and signal amplification by quantum dots for use in a biosensor assay of IgE in serumBiosensors and Bioelectronics, 2014
- A highly sensitive sensing system based on photoluminescent quantum dots for highly toxic organophosphorus compoundsRSC Advances, 2014
- A temperature sensor based on CdTe quantum dots–layered double hydroxide ultrathin films via layer-by-layer assemblyChemical Communications, 2012
- Semiconductor Quantum Dots in Chemical Sensors and BiosensorsSensors, 2009
- A simple and sensitive method for l-cysteine detection based on the fluorescence intensity increment of quantum dotsAnalytica Chimica Acta, 2009
- Biosensing and Probing of Intracellular Metabolic Pathways by NADH‐Sensitive Quantum DotsAngewandte Chemie, 2008
- Quantum dot bioconjugates for imaging, labelling and sensingNature Materials, 2005