Nitric Oxide (NO) has been identified as an intrinsic mediator to play key roles in physiological and pathological conditions in human body. Recently, the relationships between NO and diseases are attracted much attention. Due to its short half-life, the amount of NO is generally estimated from the concentrations of NO metabolites, i.e.
) and nitrate (NO3−
). The colorimetric kit (Griess method) is widely used for determination of NO2−
; however, this method is relatively complicated and time-consuming because of the intricate chemical reactions. The other methods, such as high performance liquid chromatography, are also complicated and time-consuming.Recently, in order to obtain high resolution and high speed separation of NO metabolites, some studies using capillary electrophoresis (CE) have been reported. Since, microchip CE (MCE) has an advantage in high-throughput assay, we have developed a high-throughput NO assay using MCE with UV detection.In this paper, we described the development of a novel running buffer for determination of NO2−
in human fluids, the achievement of complete MCE separation by controlling the applied voltages and the investigation of on-chip preconcentration using transient isotachophoresis. As a result, a novel running buffer based on the ionic composition of human serum was developed for CE, and then the MCE separation of NO2−
in a spiked human serum was achieved within 6.5 seconds.