Loading...

Detection of L-Dopa Based on Fluorescent of levodopa Nanopolymers and CdTe Quantum Dots

Moslehipour, Ahmad | 2015

702 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 47481 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Hormozi Nezhad, Mohammad Reza
  7. Abstract:
  8. Levodopa [L-3, 4-dihydroxyphenylalanine, or L-DOPA] is an important neurotransmitter used for the treatment of neural disorders such as Parkinson’s disease. Abnormal L-Dopa concentrations in biological fluids can be used for evaluation of diseases such as Parkinson’s diseases. In the first part of this thesis, a rapid and sensitive method for levodopa detection was reported which is based on in situ formation of polylevodopa nanoparticles. The assay is very simple and low cost and uses only NaOH and HCl as reagents. Under alkaline conditions, levodopa is spontaneously oxidized to its quinone derivative and shows the fluorescence properties. The fluorescence signal of the oxidation product of the levodopa has been explored and used for measurement of levodopa in the presence of dopamine, uric acid, ascorbic acid and other interfering which shows the excellent selectivity of the assay. The limit of detection (LOD) of the method was evaluated to be 29.0 nM with the linear range of 0.3-100.0 μM. In the second part of the research, first,, CdTe/TGA quantum dots with different size and emission spectra has been synthesized. Then, the green quantum dots have been used for levodopa detection and the red ones has been used for explaining the quenching mechanism of cdTe QDs fluorescence. Levodopa is a colorless material which is without any absorption in the visible area, but its oxidation products are yellow in the alkaline environment and have absorption in the visible area. In this method, the oxidation products of levodopa causes the quenching of quantum dots emission and the appearance of an emission peak in the wavelength of 419 nm. The calibration curve in the linear range of 0.1-12.8 μM and detection limit of 18.1 nM was derived from the ration of maximum emission intensity in the wavelength of 419 nm to maximum emission intensity of CdTe QDs. Moreover, another calibration curve was obtained from the emission intensity in the wavelength of 419 nm with linear range of 20-200 nm
  9. Keywords:
  10. Parkinson Disease ; Nanopolymer ; Neuro Transmitter ; Levodopa ; Cadmium Telluride Quantum Dots

 Digital Object List

 Bookmark

No TOC