Target-testing factor analysis of Fourier transform infrared spectra as a tool for the determination of the composition of human urinary calculi

The qualitative interpretation of the infrared spectra of urinary calculi r equires expert knowledge, and still it is not always possible to determine all the components, especially those with similar spectra that appear toget her, e.g., whewellite, CaC2O4. H2O and weddellite, CaC2O4. 2H(2)O. Instead of empirically assigning the spectra, factor analysis was employed to deter mine the number of components of urinary calculi. The method was tested on binary and ternary artificial mixtures, and then employed for assigning the composition of the human urinary calculi. The results of this work show th at the target-testing factor analysis of the infrared spectra is a promisin g method, which minimises the role of the person carrying out the analysis. (C) 1999 Elsevier Science B.V. All rights reserved.