Ferreira M. M. C., Gouterman M., Dolowy W. C., Brandes M. L., Kowalski B. R., “Chemometric study of fluorescent data by trilinear decomposition”.  Balatofüred, Hungary, 25-30/08/1996: XXIII European Congress on Molecular Spectroscopy (EUCMOS XXIII), Book of Abstracts, 221 (1996). Poster PA14.9. Section: Poster Session PA - A.14. Analytical applications, chemometrics.

M. M. C. Ferreira^*,†, M. Gouterman^*, W. C. Dolowy^*, M. L. Brandes^* and B. R.
Kowalski*
^*Dept. of Chemistry, University of Washington, Seattle WA, 98195, USA.
^†Instituto de Química, UNICAMP, Campinas SP, 13081-970, BRAZIL.

          Chemometric techniques have been applied to unresolved second order emission-
excitation fluorescent spectra of several animal dental calculus deposits (which can lead to
periodontal disease.)
          Red fluorescence has been observed in animals when dental calculus is irradiated
with ultraviolet light and preliminary analysis suggests that canine calculus contain
porphyrinic compounds although the spectra couldn't be physically resolved due to small
sample size. However, spectral resolution performed to count and separate porphyrins can
be accomplished mathematically using the trilinear decomposition method (TLD) which
performs a triadic decomposition on the data set. According to the TLD method, the true
emission, true excitation profiles and concentration ratios of the fluorescent species are
estimated. A singular value decomposition was used for preliminary indication of the
number of fluorescent species in the samples. It is clear from the chemometric analysis that
even in presence of nonlinearities, three porphyrinic spectral profiles (emission and
excitation) can be nicely attained. The method also indicates that one of the porphyrins is
common to cats and dogs while for the other two, one predominates in canine samples
while the other in the feline samples. The figures show the total luminiscent spectral
surface for one of the samples, the estimated emission and excitation profiles from all
samples together.
 
 
 

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