Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5404068 | Journal of Luminescence | 2006 | 8 Pages |
Abstract
A simpler identification method of tyrosine in the presence of tryptophan using CdS nanoparticles by conventional spectroscopic technique is proposed. Effect of both sulfide-enriched CdS as well as Cd2+-enriched CdS on tryptophan is investigated through absorption and emission spectroscopy. Quenching of tryptophan emission obeyed Stern-Volmer relation and was found to be independent of temperature, indicating a possible static quenching. The time-resolved fluorescence decay of tryptophan was minimally affected by sulfide-enriched CdS as well as Cd2+-enriched CdS nanoparticles, suggesting quenching to be static. In the presence of Cd2+-enriched CdS nanoparticles, the emission of tryptophan in phosphate buffer shows a typical spectral broadening along with a long wavelength increase in fluorescence emission. Additionally, spectra followed a typical isoemissive point at 440Â nm when tryptophan alone was there. Similarly, isoemissive point at 340Â nm was observed in the case of tyrosine. However, a further red shift of isoemissive point (470Â nm) in the mixture of both tyrosine and tryptophan was observed. This observation might make Cd2+-enriched CdS nanoparticles useful for using as marker for tyrosine in the presence of tyrptophan.
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Authors
Aparna Datta, Sudeshna Chatterjee, Ajit K. Sinha, Sudhindra N. Bhattacharyya, Abhijit Saha,