A Free Radical in Human Cerebrospinal Fluid Investigated by EPR

We have detected a free radical in human cerebrospinal fluid (CSF) and have identified as ascorbyl radical using electron paramagnetic resonance (EPR). EPR spectrum of the radical in CSF was compared with one in the corresponding serum. Determination of the ascorbyl radical concentrations in CSF and serum was attempted using known concentrations of a nitroxyl radical. Moreover, an alternative method to measure the biological radical was provided.