Flow injection method for determination of uranium in urine and serum by inductively coupled plasma mass spectrometry

The uranium concentration in urine of a population that is not occupationally exposed to uranium compounds is in the range 1-40 ng l(-1) with a median around 10 ng l(-1). This is analytically challenging for routine analysis because at such low levels it is difficult to prevent contamination during sample preparation. The method presented here is based on sample introduction via a flow injection analysis system and inductively coupled plasma mass spectrometric detection, and requires virtually no sample preparation, except for acidification of the urine sample with a few drops of HNO3. The analysis is fully automated and fast with an analysis time of 60 a per sample. The lower limit of detection is 1.5 ng l(-1). Memory and matrix effects may be decreased by adding 1 g l(-1) of a surfactant (Triton-X 100) to the carrier stream. The validity of the results is demonstrated through measurement of standard reference materials, standard dilution experiments and, at higher concentrations, by comparison with results obtained by an independent method based on laser induced fluorescence.