Separation and Detection of Peroxynitrite Using Microchip Electrophoresis with Amperometric Detection

Abstract

Peroxynitrite (ONOO⁻) is a highly reactive species implicated in the pathology of several cardiovascular and neurodegenerative diseases. It is generated in vivo by the diffusion-limited reaction of nitric oxide (NO^•) and superoxide anion (^•O₂⁻) and is known to be produced during periods of inflammation. Detection of ONOO⁻ is made difficult by its short half-life under physiological conditions (∼1 s). Here we report a method for the separation and detection of ONOO⁻ from other electroactive species utilizing a microchip electrophoresis device incorporating an amperometric detection scheme. Microchip electrophoresis permits shorter separation times (∼25 s for ONOO⁻) and higher temporal resolution than conventional capillary electrophoresis (several minutes). This faster analysis allows ONOO⁻ to be detected before substantial degradation occurs, and the increased temporal resolution permits more accurate tracking of dynamic changes in chemical systems.