345
situation is when adjacent windows have the same non-zero intensity coming from
the same peak, and a situation is possible when two adjacent common windows are
related to only two original peaks of the compared templates (in a non-trivial situation they should be related to three or four peaks). Accordingly, we monitored for
such occurrences and reduced the number of common windows appropriately. From
Figs. 12.7 and 12.8 one can see that the number of common positions for some pairs
of template spectra is relatively high, which means that the positional analysis may
not give an unequivocal answer to the question which amino acid from the corresponding pair is present in the mixture.
If the analysis using only positions of peaks is inconclusive, one can support it
with the analysis of both positions and intensities. to this end we define a correlated
pair of windows as a set of two windows corresponding to nonzero intensities for
two compared spectra, the intensities being in the same ratio for each spectrum
within a given tolerance. A number of correlated pairs can serve as a measure of
similarity between the mixture spectrum and a potential component spectrum. In
Fig. 12.8 Numbers of the common positions of 19 strongest peaks for all pairs of template spectra
of single amino acids, calculated in the range from 300 to 1700 cm
−1
. the colours reflect subdivision of the entries into three essentially equal parts defined by ranges
0 3
3 5
5 19
, ,( ,
, ( ,
which implies that the boundaries 3, 5 are 3-quantiles (tertiles)
12 Raman Spectra of Solid Aminoacids: Spectral Correlation Analysis …
situation is when adjacent windows have the same non-zero intensity coming from
the same peak, and a situation is possible when two adjacent common windows are
related to only two original peaks of the compared templates (in a non-trivial situation they should be related to three or four peaks). Accordingly, we monitored for
such occurrences and reduced the number of common windows appropriately. From
Figs. 12.7 and 12.8 one can see that the number of common positions for some pairs
of template spectra is relatively high, which means that the positional analysis may
not give an unequivocal answer to the question which amino acid from the corresponding pair is present in the mixture.
If the analysis using only positions of peaks is inconclusive, one can support it
with the analysis of both positions and intensities. to this end we define a correlated
pair of windows as a set of two windows corresponding to nonzero intensities for
two compared spectra, the intensities being in the same ratio for each spectrum
within a given tolerance. A number of correlated pairs can serve as a measure of
similarity between the mixture spectrum and a potential component spectrum. In
Fig. 12.8 Numbers of the common positions of 19 strongest peaks for all pairs of template spectra
of single amino acids, calculated in the range from 300 to 1700 cm
−1
. the colours reflect subdivision of the entries into three essentially equal parts defined by ranges
0 3
3 5
5 19
, ,( ,
, ( ,
which implies that the boundaries 3, 5 are 3-quantiles (tertiles)
12 Raman Spectra of Solid Aminoacids: Spectral Correlation Analysis …