Continuous multicomponent quantification during supercritical fluid extraction applied to microalgae using in-line UV/Vis absorption spectroscopy and on-line evaporative light scattering detection

A quantitative methodology based on in-line UV/Vis absorption spectroscopy and on-line evaporative light scattering detection for supercritical fluid extraction is proposed. The method was applied to the extraction of carotenoids, chlorophyll A, ergosterol and total lipids from microalgae. One regression technique and two curve resolution techniques were applied on the absorption spectroscopy data and evaluated, namely classical least squares, multivariate curve resolution by alternating least squares and parallel factor analysis (PARAFAC2). The two former both generated useful models, furthermore multivariate curve resolution also successfully enabled estimation of both spectra and concentration profiles of the analytes. The integrated extraction profiles of each analyte were compared with analysis of the collected fractions using reference analysis methods Precision, in regards to quantification of the analytes in the eluent, was better using in-line measurements compared to offline measurements by UV/Vis absorption spectroscopy, supercritical fluid chromatography with mass spectrometry and liquid chromatography with UV/Vis detection.