Multiway chemometric decomposition of EEM of fluorescence of CdTe quantum dots obtained as function of pH

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Joao M M Leitao (Author) Other; Helena Goncalves (Author) Other; Conceicao Mendonca (Author) Other; Joaquim C G E Esteves da Silva (Author) FCUP

Journal

Title: Analytica Chimica Acta

Vol. 628

Pages: 143-154

ISSN: 0003-2670

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 33 Citations

Scopus - 33 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-003-TYC

DOI: 10.1016/j.aca.2008.09.020

Abstract (EN): The effect of the pH (from 3 to 10) on the excitation emission matrices (EEMs) of fluorescence of CdTe quantum dots (QDs), capped with mercaptopropionic acid (MPA), were analyzed by multiway decomposition methods of parallel factor analysis (PARAFAC), a variant of the parallel factor analysis method (PARAFAC2) and multivariate curve resolution alternating least squares (MCR-ALS). Three different sized CdTe QDs with emission maximum at 555nm (QDa), 594nm (QDb) and 628nm (QDc) were selected for analysis. The three-way data structures composed of sets of EEMs obtained as function of the pH (EEMs, pH) do not have a trilinear structure. A marked deviation to the trilinearity is observed in the emission wavelength order-the emission spectra suffers wavelength shift as the pH is varied. The pH-induced variation of the fluorescence properties of QDs is described with only one-component PARAFAC2 or MCR-ALS models-other components are necessary to model scattering and/or other background signals in (EEMs, pH) data structures. Bigger sized QDs are more suitable tools for analytical methodologies because they show higher Stokes shifts (resulting in simpler models) and higher pH range sensitivity The pH dependence of the maximum wavelength of the emission spectra is particularly suitable for the development of QDs/EEMs wavelength-encoded pH sensor bioimaging or biological label methodologies when coupled to multiway chemometric decomposition.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12