Determination of long chain organic acid in degraded solvent by ion pair chromatographic method

Tri-n-butyl phosphate (TBP) dissolved in normal paraffin hydrocarbons (NPH) is used to extract uranium and plutonium from an aqueous nitric acid solution. Periodic problems in product decontamination result from solvent degradation. Undecanoic acid, lauric acid and tridecanoic acid were identified as diluent degradation products in recycle solvent. Solvent degradation studies with TBP in NPH showed that long chain organic acids and long chain alkyl butyl phosphoric acids are formed by reactions with nitric acid. These long-chain organic acids affect phase separation and lead to low decontamination factors. A simple ion-pair chromatographic method is optimized in this work for the analysis of mixture of long chain organic acids such as undecanoic acid, lauric acid and tridecanoic acid present in the degraded solvent. (author)