Band component analysis was undertaken using the Jandel
‘Peakfit’ (Erkrath, Germany) software package which enabled the
type of fitting function to be selected and allowed specific parameters
to be fixed or varied accordingly. Band fitting was done using a
Lorentz–Gauss cross-product function with the minimum number
of component bands used for the fitting process. The Lorentz–Gauss
ratio was maintained at values greater than 0.7 and fitting was
undertaken until reproducible results were obtained with squared
correlations (r2) greater than 0.995. Band fitting of the spectra is
quite reliable providing there is some band separation or changes
in the spectral profile.