Dj. Schlyer et al., IMPURITIES IN THE [O-18]WATER TARGET AND THEIR EFFECT ON THE YIELD OFAN AROMATIC DISPLACEMENT REACTION WITH [F-18] FLUORIDE, Applied radiation and isotopes, 44(12), 1993, pp. 1459-1465
Citations number
7
Categorie Soggetti
Nuclear Sciences & Tecnology","Radiology,Nuclear Medicine & Medical Imaging
Fluorine-18 in the form of fluoride ion has widespread utility in PET
radiochemistry. This paper explores the effect of possible metal ion c
ontamination of the water on the yield of the displacement of a nitro
group off of dinitrobenzene by fluoride has been investigated as a mod
el reaction for fluoride displacement. The metal ions were found to ha
ve a profound effect if they were at the level of the carbonate added
to the synthetic procedure. The yields from the reaction are best fit
by a model in which the metal ions complex the carbonate ion and thus
reduce the pH which in turn reduces the efficiency of the reaction. Th
e formation of [F-18]fluoroacetate in the target was explored as a mod
e for making the fluoride in the target unreactive. It was found that
essentially no fluoracetate was formed under our irradiation condition
s. The sources of carrier fluoride were examined. It was found that ca
rrier fluoride was introduced during the transfer of water into and ou
t of the target and not during the irradiation.