Separation and detection of peroxynitrite using microchip electrophoresis with amperometric detection

Peroxynitrite ([ONOO.sup.-]) 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.sup.*]) and superoxide anion ([sup.*][O.sub.2.sup.-]) 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.sup.-] from other electroactive species utilizing a microchip electrophoresis device incorporating an amperometric detection scheme. Microchip electrophoresis permits shorter separation times (~25 s for [ONOO.sup.-]) 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. 10.1021/ac902821v