Evaluation of different sample preparation procedures using chemometrics: comparison among photo-fenton reaction, microwave irradiation, and direct determination of minerals in fruit juices.

In this work, an exploratory study about the mineral characteristic of some fruit juice (passion fruit, pineapple, orange, and grape) applying chemometric tools was made. The juices analyzed were separated in different groups by principal components analysis and hierarchical components analysis in accordance with their minerals contents. Barium, C, Ca, K, Mg, Mn, Na, and Sr were determined by inductively coupled plasma optical emission spectrometry. Addition and recovery methods were used for confirmation of the results. The recovery range for microwave sample preparation was from 81% (for K) to 111% (for Mn), for photo-Fenton from 102% (for Ca e Mg) to 128% (for Na), and the direct analysis, without sample preparation step, from 96% (for K) to 139% (for Mn). A new method based on photo-Fenton reaction coupled with microwave radiation for juice decomposition was proposed; the obtained results were satisfactory and compatible with the conventional methods of analysis in accordance with Student's statistic t test and chemometric tools