A fast and simple method for the estimation of natural uranium in urine

Natural uranium (U) in urine was co-precipitated with Ca₃(PO₄)₂ and then with BiPO₄ after reducing uranyl ions from +6 to +4 state. U separated from BiPO₄ was then quantified by measuring its absorbance after complexing it with Arsenazo-III. The interference caused by ions such as Fe³⁺, Bi³⁺, Zn²⁺ and PO₄ ³⁻ was studied during the measurement of U absorbance. The percent recovery of U was 81.4±2.6 for 5 to 30 μg U present in 500 ml urine. The minimum detectable concentration of U was 2 μg/l and the time required to complete the analysis was 2 days.