Multivariate analysis and quantitation of O-17-nuclear magnetic resonance in primary alcohol mixtures

Multivariate techniques were used to address the quantification of O-17-nuc lear magnetic resonance (NMR) spectra for a series of primary alcohol mixtu res. Due to highly overlapping resonances, quantitative spectral evaluation using standard integration and deconvolution techniques proved difficult. Multivariate evaluation of the O-17-NMR spectral data obtained for 26 mixtu res of five primary alcohols demonstrated that obtaining information about spectral overlap and interferences allowed the development of more accurate models. Initial partial least squares (PLS) models developed for the O-17- NMR data collected from the primary alcohol mixtures resulted in very poor precision, with signal overlap between the different chemical species suspe cted of being the primary contributor to the error. To directly evaluate th e question of spectral overlap in these alcohol mixtures, net analyte signa l (NAS) analyses were performed. The NAS results indicate that alcohols wit h similar chain lengths produced severely overlapping O-17-NMR resonances. Grouping the alcohols based on chain length allowed more accurate and robus t calibration models to be developed. (C) 2000 Elsevier Science B.V. All ri ghts reserved.