A NOVEL THIN-LAYER AMPEROMETRIC DETECTOR BASED ON CHEMICALLY-MODIFIEDRING-DISC ELECTRODE AND ITS APPLICATION FOR SIMULTANEOUS MEASUREMENTSOF NITRIC-OXIDE AND NITRITE IN RAT-BRAIN COMBINED WITH IN-VIVO MICRODIALYSIS

A novel thin-layer amperometric detector (TLAD) based on chemically mo dified ring-disc electrode and its application for simultaneous measur ements of nitric oxide (NO) and nitrite (NO2-) in rat brain were demon strated in this work. The ring-disc electrode was simultaneously sensi tive to nitric oxide (NO) and nitrite (NO2-) by modifying its inner di sc with electropolymerized film of cobalt(II) tetraaminophthalocyanine (polyCoTAPc)/Nafion and its outer ring with poly(vinylpyridine) (PVP) : respectively. The ring-disc electrode was used to constitute a novel TLAD in radial flow cell for simultaneous measurements of NO and NO2- in rat brain combined with techniques of high performance liquid chro matography (HPLC) and in vivo microdialysis. It was found that the bas al concentration of NO in the caudate nucleus of rat brain is lower th an 1.0 x 10(-7) mol l(-1), NO2- concentration is 5.0 x 10(-7) mol l(-1 ) and NO exists in brain maybe mainly in the form of its decomposed pr oduct. (C) 1998 Elsevier Science B.V. All rights reserved.