| Popis: |
[15N]nitric oxide for investigations on the effect of nitric oxide in biological systems can be synthesized economically from the commercially available [15N]nitric acid. Difficulties arise, however, for the preparation of highly enriched 15N-labelled nitric oxide on a lower mmol scale. These difficulties are caused by oxygen and result in both, yield depression and insufficient long-time stability of the NO-containing gas mixture due to its oxidation to NO2. Therefore, a sensitive in situ oxygen detection during synthesis was carried out by on line coupling of the synthesis apparatus with a GC-MS. Additionally, this equipment offers the advantage that both, conversion and 15N enrichment may be measured almost continuously and simultaneously. In this way, the yield can be increased up to 85% without increasing by-products. The gas mixture prepared from this [15N]nitric oxide showed an adequate stability for several months at a concentration of about 100 ppm(v) NO. |
