Provider: ingentaconnect
Database: ingentaconnect
Content: application/x-research-info-systems
TY - ABST
AU - Haaland, David M.
AU - Easterling, Robert G.
AU - Vopicka, David A.
TI - Multivariate Least-Squares Methods Applied to the Quantitative Spectral Analysis of Multicomponent Samples
JO - Applied Spectroscopy
PY - 1985-01-01T00:00:00///
VL - 39
IS - 1
SP - 73
EP - 84
KW - Esters
KW - Computer, applications
KW - Quantitative infrared spectroscopy
KW - Least-squares analysis
N2 - In an extension of earlier work, weighted multivariate least-squares methods of quantitative FT-IR analysis have been developed. A linear least-squares approximation to nonlinearities in the Beer-Lambert law is made by allowing the reference spectra to be a set of known mixtures. The
incorporation of nonzero intercepts in the relation between absorbance and concentration further improves the approximation of nonlinearities while simultaneously accounting for nonzero spectral baselines. Pathlength variations are also accommodated in the analysis, and under certain conditions,
unknown sample pathlengths can be determined. All spectral data are used to improve the precision and accuracy of the estimated concentrations. During the calibration phase of the analysis, pure component spectra are estimated from the standard mixture spectra. These can be compared with the
measured pure component spectra to determine which vibrations experience nonlinear behavior. In the predictive phase of the analysis, the calculated spectra are used in our previous least-squares analysis to estimate sample component concentrations. These methods were applied to the analysis
of the IR spectra of binary mixtures of esters. Even with severely overlapping spectral bands and nonlinearities in the Beer-Lambert law, the average relative error in the estimated concentrations was <1%.
UR - http://www.ingentaconnect.com/content/sas/sas/1985/00000039/00000001/art00015
M3 - doi:10.1366/0003702854249376
UR - http://dx.doi.org/10.1366/0003702854249376
ER -