Electrooxidation behavior and electrochemistry determination method of the xanthophylls: Lutein in nonaqueous media

The electrooxidation behavior and determination of lutein, which is an important botanical pigment and antioxidant, were investigated by electrochemical method in nonaqueous media for the first time. The electrooxidation of lutein is a diffusion-controlled irreversible reaction. The electrochemical method shows some selectivity for lutein and lutein esters due to their different end structures, and can be applied to discrimination and qualitative detection of the two, which cannot be achieved by the spectrophotometry. Besides, using differential pulse voltammetry, anodic currents of lutein are linear with their concentration in the range of 0.5–76 μM, with detection limits of 0.1 μM. The proposed determination method has been successfully applied in the real sample analysis with good sensitivity and reproducibility, confirming it should be a useful addition to the analytical methodology available for monitoring the concentrates of lutein.