Determination of uranium in urine and water samples

Monitoring internal contamination of workers professionally exposed to uranium or other sources of radioactive products has been one of the concerns of radiation protection for over half a century. In the last decade and due to several global conflict situations, this concern was expanded to members of the population none or semi professionally exposed to uranium contamination (e.g. use of depleted uranium ammunition in war zones near civil or military installations). A rapid, high precision and highly sensitive measurement technique allowing for high sample throughput is therefore needed. TR-KPA (Time Resolved Kinetic Phosphorescence Analysis) is such a technique. It allows for the measurement of small amounts of uranium (down to 0.1 micrograms per litre) with good precision and accuracy (less than 20 % expanded uncertainty) in a great variety of sample matrices (water samples, urine samples, blood samples). The main objective for SCK-CEN's analytical laboratories of the Department of Low Level Radioactivity Measurements was to replace the existing measurement technique for uranium in urine samples (alkaline fusion, followed by fluorimetric determination) by the TR-KPA technique to improve the reliability of the analytical results and to lower the limit of quantification (from 1 microgram per litre for the fluorimetric method to 0.1 micrograms per litre for the TR-KPA technique). The implementation of the TR-KPA technique was therefore extensively validated, especially concerning the sample preparation and the relevant parameters such as linearity, limit of detection, precision, accuracy, reproducibility, repeatability and robustness. Principal results are discussed