Optimización experimental de un método cromatográfico HPLC-DAD para el análisis de polifenoles en frutas

Abstract

The aim of the present study was to develop and optimize a HPLC-DAD method for the analysis of polyphenols in fruits. For the experiments, standards of nine phenolic compounds were used, initial runs were performed with conditions based on scientific papers. Method optimization was carried out by using a factorial design, followed by a central composite design and a desirability test to determine the influence of the variables flow rate, column temperature and acidification of the mobile phase on the response variable efficiency. Through the optimization tests, the optimal chromatographic conditions proposed by the models were determined. Next, the optimized analytical method was applied on lyophilized mango samples extracted by a method developed utilizing literature review. In the factorial design, a low adjustment of the model was observed and the variable acidification of the mobile phase was not significant. There was an adjustment improvement with the composite central design. A heterogeneous influence of the variables analyzed on the chromatographic efficiency was demonstrated. The desirability test proposed the optimal conditions of 0.64 mL / min for the flow rate and 29.1°C for the column temperature, this proposal was of little applicability for practical reasons. At last, a final method of 43.5 min was obtained at the optimal wavelengths of 254, 280 and 320 nm. Chromatograms with resolved peaks were obtained for mango samples with an acceptable variation (4.4 - 7.6% CV), denoting the applicability of the optimized method and the utility of the extraction method. In the samples, 4 out of 9 phenolic compounds analyzed were identified and quantified. On the other hand, the need for corroboration of analytical recovery and application of the method in other matrices was observed.