A new application of X-ray scattering using principal component analysis - classification and identification of liquid precursor chemicals

X-ray scattering (XRS) combined with principal component analysis has been utilized for classifying and identifying liquid precursor chemicals for the first time. The XRS spectra of some liquid precursor chemicals and normal materials were obtained by using an XRS system, and the profiles of scattering media distinctly reveal that the XRS spectra are unique corresponding to the specific liquid material. Furthermore, the obtained spectra were processed through principal component analysis by using the selected energy region in the spectra. The score plots of each substance were clustered together and almost coincident for the same liquid, implying good repeatability and reliability. As far as the different liquid materials are concerned, they could be classified into distinct groups according to their positions in the score plot. The score plots showed a clear classification and recognition of liquid precursor chemicals. This study demonstrates a possibility for analyzing different liquid materials, and it presents a new application for X-ray spectroscopy. Copyright (C) 2012 John Wiley & Sons, Ltd.