Evaluation of the total antioxidant capacity by using a multipumping flow system with chemiluminescent detection

Abstract

An automated flow-based procedure for assessment of total antioxidant capacity was developed. It involved a multipumping flow system, a recent approach to flow analysis, and exploited the ability of selected compounds to inhibit the chemiluminescence reactions of luminol or lucigenin with hydrogen peroxide. The system included several discretely actuated solenoid micropumps as the only active components of the flow manifold. This enabled the reproducible insertion and efficient mixing of very low volumes of sample and reagents as well as the transportation of the sample zone toward a flow-through luminometer, where the chemiluminometric response was monitored. With luminol as the chemiluminogenic reagent, linearity of the analytical curves was noted up to 3.2 × 10 −4, 1.1 × 10 −3, and 8.8 × 10 −8 mol L −1 for Trolox, ascorbic acid, and resveratrol, respectively. With lucigenin, linear calibration plots up to 2 × 10 −5 mol L −1 of Trolox and 5.7 × 10 −5 mol L −1 of ascorbic acid were obtained. As favorable analytical figures of merit, the measurement precision (RSD typically between 0.2 and 2.0%, n = 10), low operational costs, low reagent consumption, sampling rate (160 and 70 h −1), and versatility should be highlighted. The proposed system can be used in distinct analytical circumstances without requiring physical reconfiguration.