Multivariate analysis of attenuated total reflection spectra of Norway spruce needles

Single bounce horizontal ATR FT-IR spectroscopy was used to study a waxy la yer on the surface of individual Norway Spruce needles. The role of several variables, namely the position of the twig on the branch, place of the mea surement on the needle, age, order of measurement (before or after the NIR Raman spectroscopy), fixation pressure on the needle during the measurement and selected wavenumber range in spectra variability was estimated from SI MCA classification of PCA models created from 750 ATR spectra, Surprisingly , only the age of the needle and position of the one-year-old twig are impo rtant in classification. (C) 2001 Elsevier Science B.V. All rights reserved .