Este trabajo presenta una metodologı´a para medir simulta´neamente el contenido total de tres clases de compuestos
feno´ licos (a´cidos hidroxibenzoicos, a´cidos hidroxicina´micos y flavonoides), ası´ como el contenido feno´ lico total usando
un solo espectro UV-Vis. Para probar la metodologı´a, se utilizaron muestras de propo´ leos. En primer lugar, un disen˜o
experimental basado en la metodologı´a de la respuesta en superficie establecio´ que la mejor solucio´n hidroetano´ lica
para la extraccio´n de compuestos feno´ licos de propo´ leos tenı´a un 80% de etanol. En segundo lugar, se desarrollaron
modelos de calibracio´n con regresio´n lineal mu´ ltiple, junto con el algoritmo de saltos para la seleccio´n variable, utilizando
espectros UV-Vis de soluciones esta´ndar mixtas (a´cido ga´lico, a´cido feru´lico y mezclas de quercetina), todas
con concentraciones ortogonales establecidas por un disen˜o factorial fraccional multinivel. La estimacio´n del modelo y
el rendimiento de la prediccio´n tenı´an linealidad entre los valores de concentracio´n previstos y esperados, con una
pendiente que variaba de 0,996 a 1,04 y coeficientes de determinacio´n superiores a 0,995. Una solucio´n de control de
calidad presento´ aceptable repetibilidad y precisio´n (porcentaje de desviacio´n esta´ndar relativa y porcentaje de error
relativo inferiores al 4,8%). El ana´lisis de extractos de compuestos feno´ licos de propo´ leos mostro´ una precisio´n aceptable
(porcentajes de desviacio´n esta´ndar relativa inferior al 1,6%) y una precisio´n aceptable (los ensayos de recuperacio
´n variaron entre 98 y 112%). En general, la presente te´cnica analı´tica multiparame´trica puede ser un primer
enfoque para la caracterizacio´n quı´mica de extractos de compuestos feno´ licos, como el obtenido a partir de las muestras
de propo´ leos, considerando sus ventajas de simplicidad, rapidez, precisio´n y precisio´ n. Adema´s, esta metodologı´a
puede adaptarse a otras matrices de muestra, siempre que los espectros de absorcio´n UV-Vis tı´picos de sus clases de
compuestos feno´ licos muestren solapamiento parcial, permitiendo la calibracio´n multivariante.
This work presents a methodology for simultaneously measuring the total content of three classes of phenolic compounds
(hydroxybenzoic acids, hydroxycinamic acids and flavonoids), as well the total phenolic content using a single UVvis
spectrum. To test the methodology, samples of propolis were used. Firstly, an experimental design based in the
Response Surface Methodology established that the best hydroethanolic solution for propolis phenolic compounds
extraction had 80% of ethanol. Secondly, calibration models were developed with multiple linear regression, coupled with
the leaps algorithm for variable selection, using UV-vis spectra of mixed standard solutions (gallic acid, ferulic acid and
quercetin mixtures), all with orthogonal concentrations established by a multilevel fractional factorial design. The model’s
estimation and prediction performance had linearity between predicted and expected concentration values, with slope
ranging from 0.996–1.04 and determination coefficients higher than 0.995. A quality control solution presented acceptable
repeatability and accuracy (relative standard deviation percentage and percentage relative error were lower than
4.8%). Analysis of propolis phenolic compounds extracts showed acceptable precision (relative standard deviation percentages
lower than 1.6%) and acceptable accuracy (recoveries assays ranged between 98 and 112%). Overall, the present
multi-parametric analytical technique can be a first approach for chemical characterization of phenolic compounds
extracts, such as that obtained from the propolis samples, considering its advantages of simplicity, rapidity, precision and
accuracy. Moreover, this methodology can be adapted to other sample matrices, provided that the typical UV-vis absorption
spectra of their classes of phenolic compounds shows partial overlapping, allowing multivariate calibration.
This work was financially supported by CQ-VR, Centro de
Química – Vila Real, University of Trás-os-Montes e Alto
Douro [Project UID/QUI/00616/2013]; Centre of Molecular
and Environmental Biology, University of Minho [Project UID/
BIA/04050/2013]; funded by FEDER (Fundo Europeu de
Desenvolvimento Regional) through COMPETE2020 (Programa
Operacional Competitividade e Internacionalização, POCI); by
national funds through FCT (Fundação para a Ciência e a Tecnologia,
Portugal); by Project 56343–“New products derived
from sausage”, Measure 4.1 – Cooperation for Innovation,
PRODER program, Portugal.
