The resolution of quaternary mixtures of chlorophylls a and b and pheophytins a and b has been accomplished by partial least-squares (PLS) multivariate calibration, applied to the fluorescence signals of these pigments. The total luminescence information of the compounds has been used to optimize the spectral data set to perform the calibration. After preliminary studies, a method is described in acetone media, to avoid emulsions with the olive oil samples. Different scanning paths have been selected 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 spectral data, as analytical signal, was performed. The excitation spectra were selected as the better analytical signals for the determination of the pigments in olive oil samples. The optimum wavelength range to record the excitation spectra (lambda(em) = 662 nm) was selected to minimize the contribution of pheophytin a and to maximize the contribution of the other pigments, which are the minor constituents in olive oil. Determination of these pigments in olive oil samples was effected from the excitation spectra of dissolutions o suitable aliquots in acetone. Recovery values from olive oil, spiked with chlorophylls a and b and pheophytins a and b, were in the ranges of 70-112, 71-111, 76-105, and 82-109%, respectively.

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SummaryA micellar electrokinetic capillary chromatography (MEKC) method has been developed for quantification of four drugs -tamoxifen, anastrozole, letrozole, and methotrexate -used to treat advanced breast cancer. Separation was performed at 25 ~ and 25 kV, with 20 mM borate buffer (pH 9.2) containing 40 mM sodium dodecylsulfate as electrolyte solution. Under these conditions analyses were performed in 12 min. The hnearity of the response was investigated for the concentration range 2.0-20.0 mg L 1. The intra-day residual standard deviation (n = 4 graphs) bel',,veen the slopes of the calibration graphs was acceptable for the four drugs studied. Detection limits (signal-to-noise ratio = 3) were below 1 mg L 1 for all the compounds. The simplicity, precision, and sensitivity of MEKC proved suitable for quahty control of pharmaceutical preparations used to treat advanced breast cancer. Six different pharmaceutical preparations, each containing one of the above-mentioned drugs, were successfully analyzed.

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