Rapid Separation and Quantification of Iron in Uranium Nuclear Matrix by Capillary Zone Electrophoresis (CZE)

A method was developed for rapid separation and determination of iron by employing capillary zone electrophoresis (CZE) technique with direct UV detection. Iron could be separated from matrix uranium by direct injection of dissolved sample solution into capillary using a mixture of 10 mM HCl and 65 mM KCl (pH = 2) as background electrolyte (BGE) at an applied voltage of 15 kV. The developed method has a very high tolerance for the matrix element U (100 mg/mL) and as such may not need prior separation of iron from the matrix. Iron could be separated with better than 95% recovery. The method showed a linear calibration over a concentration range 1-50 ppm of Fe(III). The migration times for the iron peak were reproducible within 1% for both pure Fe(III) and in presence of matrix uranium (80 mg/mL). The precision (RSD, n = 22) of peak area obtained for 1 ppm of iron was 3.5%. The limit of detection (LOD) (3) was 0.1 ppm and the absolute LOD was 9 × 10 g considering the sample injection volume of 1.5 nL. The developed method has been validated by separating and determining iron in two certified reference materials of U3O8. The method was applied for the determination of iron in different uranium based nuclear materials. The CZE method is versatile for routine analysis as it is simple, rapid and has simple sample preparation procedure.