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CdTe Quantum Dots Modified with Cysteamine: A New Efficient Nanosensor for the Determination of Folic Acid

Authors :
Georgina Pina-Luis
Doris E. Ramírez-Herrera
Giselle Dominguez
Antonio Tirado-Guízar
Francisco Paraguay-Delgado
Ana Patricia Reyes-Cruzaley
Source :
Sensors, Volume 19, Issue 20, Sensors (Basel, Switzerland), Sensors, Vol 19, Iss 20, p 4548 (2019)
Publication Year :
2019
Publisher :
Multidisciplinary Digital Publishing Institute, 2019.

Abstract

In this paper, we report the synthesis, characterization, and application of a new fluorescent nanosensor based on water-soluble CdTe quantum dots (QDs) coated with cysteamine (CA) for the determination of folic acid (FA). CdTe/CA QDs were characterized by high-resolution transmission electron microscopy, the zeta potential, and Fourier-transform infrared (FT-IR), UV-visible, and fluorescence spectroscopy. CdTe QDs coated with mercaptopropionic acid (MPA) and glutathione (GSH) were prepared for comparison purposes. The effect of FA on the photoluminescence intensity of the three thiol-capped QDs at pH 8 was studied. Only CdTe/CA QDs showed a notable fluorescence quenching in the presence of FA. Then, a nanosensor based on the fluorescence quenching of the CdTe QDs at pH 8 was explored. Under optimum conditions, the calibration curve showed a linear fluorescence quenching response in a concentration range of FA from 0.16 to 16.4 &mu<br />M (R2 = 0.9944), with a detection limit of 0.048 &mu<br />M. A probable mechanism of fluorescence quenching was proposed. The nanosensor showed good selectivity over other possible interferences. This method has been applied for FA quantification in orange beverage samples with excellent results (recoveries from 98.3 to 103.9%). The good selectivity, sensitivity, low cost, and rapidity make CdTe /CA QDs a suitable nanosensor for FA determination.

Details

Language :
English
ISSN :
14248220
Database :
OpenAIRE
Journal :
Sensors
Accession number :
edsair.doi.dedup.....f6b7da09b9c3cf0ab668531fb63e8360
Full Text :
https://doi.org/10.3390/s19204548