title: Reversed-phase liquid chromatography using mandelic acid as an eluent for the determination of uranium in presence of large amounts of thorium.
abstract: Studies were carried out for the separation of uranium (U) and thorium (Th) on reversed-phase (RP) C18 columns using mandelic acid as an eluent. Retention of thorium-mandelate on the unmodified stationary phase was found to be greater than that of uranyl-mandelate under the pH conditions employed. Th retention capacity of the stationary phase was determined as a function of pH and MeOH content of the mobile phase. The optimised parameters allowing U elution prior to Th were utilized for the determination of small amounts of U in the presence of large amounts of Th. The method has been used for the determination of U in synthetic samples with Th/U amount ratios up to 100,000 (10 microg/g of U) without any pre-separation, employing a particulate C18 column. Effect of concentration of ion interaction reagents (IIRs) on the retention was studied to understand the mechanism of adsorption of their mandelate complexes onto the stationary phase. The experiments conducted unequivocally prove that thorium-mandelate complex is neutral whereas uranyl-mandelate complex is anionic in nature.
authors.affiliation: Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India. pg jaison@yahoo.com
authors.forename: P G
authors.initials: PG
authors.lastname: Jaison
authors.forename: Vijay M
authors.initials: VM
authors.lastname: Telmore
authors.forename: Pranaw
authors.initials: P
authors.lastname: Kumar
authors.forename: Suresh K
authors.initials: SK
authors.lastname: Aggarwal
mesh_terms: D000327:Adsorption; D017738:Alkanesulfonic Acids / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008333:Mandelic Acids / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D009994:Osmolar Concentration; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D013910:Thorium / Q000032:analysis* / Q000302:isolation & purification; D014501:Uranium / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D017738:Alkanesulfonic Acids; D008333:Mandelic Acids; D000644:Quaternary Ammonium Compounds; D014501:Uranium; D013910:Thorium; C009405:tetrabutylammonium; C042005:1-octanesulfonic acid; C037938:mandelic acid; D000432:Methanol