Electrochemical Determination of Low-Molecular-Weight Antioxidants in Blood Serum

Abstract

The aim of the study was to establish and optimize an electrochemical method for the assay of low-molecular-weight antioxidants (LMWA). We used square-wave vol­tammetry (at 0–1.1 V) on screen-printed sensors with C working electrodes. Optimum parameters were: potential step and amplitude 5 mV and frequency 1 Hz. Ascorbic acid, trolox, N-acetylcysteine and melatonin were used as standard antioxidants to test the linearity and sensitivity of the method. Limits of detection were 0.09 mmol l^–1 for ascorbic acid, 0.04 mmol l^–1 for melatonin, 0.03 mmol l^–1 for trolox, and 0.07 mmol l^–1 for N-acetylcysteine. 20 μl samples were used. The suitability of the method for the assay was confirmed by the standard ferric reducing ability of plasma test. Both methods correlated well (correlation coefficient 0.9778).