IDENTIFICATION OF ISOMERIC TRIBUTYLPHOSPHATE DIMERS FORMED BY RADIOLYSIS USING TANDEM MASS-SPECTROMETRY AND STABLE ISOTOPIC LABELING

Tributylphosphate (TBP) dimers, formed during radiolysis of the nuclea r fuel reprocessing solvent, were studied using tandem mass spectromet ry (MS/MS), stable isotopic labelling (H-2) and synthetic model compou nds, The structures of isomeric diners and their lower homologues were established, using GC/MS as well as electron impact and chemical ioni sation GC/tandem mass spectrometry, with an extensive use of ion chrom atograms of characteristic fragment ions from collision-induced decomp osition in both non-deuterated and selectively deuterated series. An e xplanation of isomer ratios and of the restricted number of lo,ver hom ologues as well as a radiolytic mechanism are advanced. The TBP-dimer fraction represented less than similar to 0.03% of the total mixture o btained from radiolysis of solvent.