Separation and Detection of Peroxynitrite Using Microchip Electrophoresis with Amperometric Detection

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 center dot) and superoxide anion (O-center dot(2)-) and is known to be produced during periods of inflammation. Detection of ONOO- is made difficult by its short half-life under physiological conditions (similar to 1 s). Here we report it 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 (similar to 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.