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María del Pilar Godoy-Caballero María Julia Culzoni Teresa Galeano-Díaz María Isabel Acedo-Valenzuela 《Analytica chimica acta》2013
This paper presents the development of a non-aqueous capillary electrophoresis method coupled to UV detection combined with multivariate curve resolution-alternating least-squares (MCR-ALS) to carry out the resolution and quantitation of a mixture of six phenolic acids in virgin olive oil samples. p-Coumaric, caffeic, ferulic, 3,4-dihydroxyphenylacetic, vanillic and 4-hydroxyphenilacetic acids have been the analytes under study. All of them present different absorption spectra and overlapped time profiles with the olive oil matrix interferences and between them. The modeling strategy involves the building of a single MCR-ALS model composed of matrices augmented in the temporal mode, namely spectra remain invariant while time profiles may change from sample to sample. So MCR-ALS was used to cope with the coeluting interferences, on accounting the second order advantage inherent to this algorithm which, in addition, is able to handle data sets deviating from trilinearity, like the data herein analyzed. The method was firstly applied to resolve standard mixtures of the analytes randomly prepared in 1-propanol and, secondly, in real virgin olive oil samples, getting recovery values near to 100% in all cases. The importance and novelty of this methodology relies on the combination of non-aqueous capillary electrophoresis second-order data and MCR-ALS algorithm which allows performing the resolution of these compounds simplifying the previous sample pretreatment stages. 相似文献
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Conservative methods for the Toda lattice equations 总被引:1,自引:0,他引:1
We are concerned with the numerical integration of the Todalattice equations by using different conservative methods. Numericalexperiments suggest that the global error for isospectral schemesdecreases exponentially with time but it is almost constantfor either symplectic or more general integrators. We providea theoretical explanation for these experimental findings. 相似文献
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Godoy-Caballero MP Acedo-Valenzuela MI Durán-Merás I Galeano-Díaz T 《Analytical and bioanalytical chemistry》2012,403(1):279-290
Response surface methodology has been applied to the optimization of a simple and rapid non-aqueous capillary electrophoresis
method for the separation and determination of several phenolic compounds belonging to the different families present in olive
oil. A Box–Behnken design was employed and a total of 27 experiments were performed using olive oil samples spiked with the
phenols and injected directly in the capillary after dilution 1:1 with 1-propanol. Finally, the background electrolyte (BGE)
was constituted of 25 mM boric acid and 18 mM KOH in a mixture of 74:26 (v/v) 1-propanol/methanol. The hydrophobicity of the BGE allows its miscibility with the olive oil and, as a consequence, the
possibility of characterizing and determining these kinds of compounds in this sample without any pretreatment. A hydrodynamic
injection (6 s, −30 mbar) was applied and the separation was carried out using 35 °C and +20 kV of separation temperature
and voltage, respectively. A capillary with two detection windows for serial online UV and fluorescence detection was satisfactorily
employed. The validation of the method was carried out by setting the calibration curves, and the figures of merit were finally
obtained. A lineal relationship between the corrected peak area and concentration and limits of detection in the order of
micrograms per milliliter were found. 相似文献
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