Ion chromatographic determination of di-butyl phosphate (DBP) and mono-butyl phosphate (MBP) in organic waste generated during metallic impurity assay of PFBR MOX

AFFF is fabricating (U, Pu)O₂ MOX fuel for PFBR. Trace metallic impurities in PFBR MOX fuel are assayed by ICP-AES technique after major matrix separation by 30% tributylphosphate(TBP) in n-dodecane. Tributyl phosphate (TBP) undergoes degradation in to dibutyl phosphate (DBP), monobutyl phosphate (MBP) and phosphoric acid by radiolysis and hydrolysis. This diminishes the extraction properties of TBP for the extraction of uranium and plutonium. Hence it is important to determine DBP and MBP in 30% TBP in n-dodecane. Gas chromatography (GC) is widely used technique for the determination of DBP but it is time consuming. Ion chromatographic technique utilizes the anionic properties of DBP and MBP in basic media for their separation on anion exchange resin followed by ion conductivity measurement. Present paper describes the IC separation of DBP, MBP on MetrosepSupp 5 (250 x 4 mm) column using Na₂CO₃ + NaOH as mobile phase and their quantitative determination using suppressed conductivity detection after CO₂ suppressor