Phosphoric acid as uranium complexant in kinetic phosphorimetry

Phosphorimetry is an analytical technique for the determination of elemental uranium concentration in aqueous environmental or biological samples. Uranium phosphorescence from aqueous samples at room temperature is practically undetectable without the addition of a uranium complexant, i.e., a solution whose molecules bind to the uranyl ions present in the sample under measurement and protect them from non-luminescent de-excitation. Procurement of commercially available and proprietary in nature complexant solutions can prove cost in-effective. On the other hand, phosphoric acid is known for its phosphorescence protecting capabilities. This study investigates the optimisation of phosphoric acid use as uranium complexant, and assesses it in terms of accuracy, precision and longevity, with rather encouraging results.