| Abstract
| - The resolution of quaternary mixtures of chlorophylls a and b and pheophytins a and b has beenaccomplished by partial least-squares (PLS) multivariate calibration, applied to the fluorescence signalsof these pigments. The total luminescence information of the compounds has been used to optimizethe spectral data set to perform the calibration. After preliminary studies, a method is described inacetone media, to avoid emulsions with the olive oil samples. Different scanning paths have beenselected for each method. For the simultaneous determination of the pigments in olive oil samples,a comparative study of the results found by using excitation, emission, and synchronous spectraldata, as analytical signal, was performed. The excitation spectra were selected as the better analyticalsignals for the determination of the pigments in olive oil samples. The optimum wavelength range torecord the excitation spectra (λem = 662 nm) was selected to minimize the contribution of pheophytina and to maximize the contribution of the other pigments, which are the minor constituents in oliveoil. Determination of these pigments in olive oil samples was effected from the excitation spectra ofdissolutions o suitable aliquots in acetone. Recovery values from olive oil, spiked with chlorophylls aand b and pheophytins a and b, were in the ranges of 70−112, 71−111, 76−105, and 82−109%,respectively. Keywords: Chlorophylls; pheophytins; fluorescence; partial least-squares; olive oil
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