Thioglycolic Acid-Capped CdS Quantum Dots Conjugated to α-Amylase as a Fluorescence Probe for Determination of Starch at Low Concentration

In the present research, water soluble thioglycolic acid-capped CdS quantum dots (QDs) were synthesized by chemical precipitation method. The characteristics of prepared quantum dots were determined using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The obtained results reveal...

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Bibliographic Details
Published in:Journal of fluorescence 2016-09, Vol.26 (5), p.1787-1794
Main Authors: Tayebi, Mahnoush, Tavakkoli Yaraki, Mohammad, Mogharei, Azadeh, Ahmadieh, Mahnaz, Tahriri, Mohammadreza, Vashaee, Daryoosh, Tayebi, Lobat
Format: Article
Language:English
Subjects:
Analytical Chemistry
Biochemistry
Biological and Medical Physics
Biomedical and Life Sciences
Biomedicine
Biophysics
Biotechnology
Cadmium sulfide
Original Article
Photoluminescence
Quantum dots
Transmission electron microscopy
X-ray diffraction
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Summary:In the present research, water soluble thioglycolic acid-capped CdS quantum dots (QDs) were synthesized by chemical precipitation method. The characteristics of prepared quantum dots were determined using X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The obtained results revealed that CdS QDs have 5.60 nm crystallite size, hexagonal wurtzite structure and spherical morphology with less than 10 nm diameter. The photoluminescence (PL) spectroscopy was performed in order to study the effect of the presence of starch solutions. Blue emission peaks were positioned at 488 nm and its intensity quenched by increasing the concentration of starch solutions. The result of PL quenches in range of studied concentrations (0–100 ppm) was best described by Michaelis-Menten model. The amount of Michaelis constant (K m ) for immobilized α-amylase in this system was about 68.08 ppm which showed a great tendency of enzyme to hydrolyze the starch as substrate. Finally, the limit of detection (LOD) was found to be about 2.24 ppm.
ISSN:1053-0509
1573-4994
DOI:10.1007/s10895-016-1870-8