The application of fourier-transformed near-infrared spectra to quantitative analysis by comparison of similarity indices (CARNAC)

A new technique for utilising near-infrared spectroscopic data for quantitative analysis is proposed. The method uses a database of spectra stored in the form of the Fourier transform together with the associated chemical analysis. The spectrum of an unknown sample is compared to each member of the database and a small subset of very similar samples is isolated. The analyte value for the unknown is calculated from the analytical values of the subset. Results are given for the application of the method to the analysis of nicotine in tobacco.