A RP-HPLC method using α-Hydroxy isobutyric acid for preconcentration and determination of uranium in seawater

Abstract

A high-performance liquid chromatographic (HPLC) method is developed for the determination of uranium (U), present at ppb levels, in seawater. α-Hydroxy isobutyric acid is used as the complexing agent for preconcentration as well as separation of U from other interfering metal ions (Mo, V, Ti, Ni etc.). A C18 reversed-phase monolithic column and α-HIBA of pH 6-7 are employed for the selective preconcentration of U. Mobile phase consisting of α-HIBA of pH 2 and MeOH is used for elution of adsorbed U which is monitored after post-column derivatisation with Arsenazo(III), using a spectrophotometric detector. The methodology is validated by using simulated as well as seawater samples. Quantitative recovery for U is possible with linear response over a concentration range of 1 to 30 ppb of U. Metal ions which have been previously reported to give interferences do not give any problem in the present approach. The developed HPLC methodology is validated by comparing the results with those of isotope dilution-thermal ionization mass spectrometry.