Comparison between a new application of multivariate regression and current spectroscopy methods for the determination of chlorophylls and their corresponding pheopigments Original Research Article

A multivariate calibration model, partial least squares regression for several independent variables (PLS2), has been developed for the simultaneous determination of chlorophyll a, b and c and the corresponding pheophytin a and b and pheoporphyrin c. Mixtures with these six components were prepared at four concentration levels with respect to each analyte, in acetone:water. The concentration for chlorophyll a varied from 1 to 7 mg l−1. Absorbance spectra in the visible range, 350–770 nm, were registered. The predictive ability, reported as the root mean square error of prediction (RMSEP), was found to be 0.167 mg l−1 for chlorophyll a. Similar results were found for the other analytes. The spectral data were also evaluated with the absorption spectroscopy procedures recommended in Standard Methods for the Examination of Water and Wastewater. For chlorophyll a, the proposed multivariate method improved the predictive ability by a factor 2.4. Data is available at: