NEAR NEAR-INFRARED SPECTROSCOPY FOR QUANTITATIVE AND QUALITATIVE QUALITY-CONTROL

Absorbance spectra from near near infrared (NNIR; 800-1050 nm) spectroscopy of organic liquids are measured using a silicon diode array spectrometer. No sample dilution is necessary as the absorbance values are low. Multi-component analysis applied to complete NNIR spectra provides both quantitative and qualitative information, essential in industrial quality control. Acceptable accuracy (error <1 %) is achieved in the quantitative analysis of mixtures of non-interacting substances, and it is also possible to analyse alcohols in non-polar solvents, where intermolecular H-bonding occurs. Principal component regression was also performed on the NNIR data to give qualitative information.