Determination of multiple redox-active compounds by high-performance liquid chromatography with coulometric multi-electrode array system

Studies of the antioxidant defense system and the related metabolic pathways are often complicated by cumbersome analytical methods, which require separate and multi-step extraction and chemical reaction procedures. Further, assaying multiple parameters is limited because of the usual small sample amounts. High-performance liquid chromatography coupled with a coulometric multi-electrode array system provides us high specificity and sensitivity to measure electrochemically oxidizable compounds in biological samples. In contrast to previously reported methods with two columns in series and a complex gradient elution profile, we have developed an automated procedure to simultaneously measure multiple redox-active low-molecular weight compounds that utilizes a single column with a simplified binary gradient profile. No other chemical reactions are necessary. In order to reduce the running time and yet achieve a reproducible retention time by the auto sampler injection, our gradient elution profile was modified to produce a shorter equilibration time, stable retention time, and a reduced cost per test.