RESUMO
This paper examines for the first time the analytical possibilities of fast and simultaneous detection of prominent natural antioxidants including examples of flavonoids and vitamins using a CE microchip with electrochemical detection (ED). Unpinched injection conditions, zone electrophoretic separation and amperometric detection were carefully assayed and optimised. Analysis involved the zone electrophoretic separation of arbutin, (+)-catechin and ascorbic acid in less than 4 min using a borate buffer (pH 9.0, 50 mM), employing 2 kV as the separation voltage and +1.0 V as the detection potential. In addition, the separation of different 'couples' of natural antioxidants of food significance including (+)-catechin and ascorbic acid, (+)-catechin and rutin, as well as arbutin and phlorizdin is proposed. To demonstrate the potential and future role of CE microsystems, analytical possibilities and a new route in the raw sample analysis are presented. The preliminary results obtained allow the proposal of CE-ED microchips as a real gateway to microanalysis in foods.