CHROMIUM DETERMINATION IN NIST STANDARD URINE BY RESONANCE IONIZATIONMASS-SPECTROMETRY

The technique of resonance ionization mass spectrometry (RIMS) has bee n applied to elemental chromium determination in standard (NIST) human urine samples. RIMS combines multistep photoionization with mass spec tral sorting and detection of the resultant ions to provide high sensi tivity and selectivity. The Cr concentration in a NIST standard urine sample has been determined using RIMS/isotope dilution techniques to b e 0.093 +/- 0.008 mug/ml in good agreement with the 0.085 +/- 0.006 mu g/ml certified value. The results indicate the utility and selectivity of RIMS in isotope dilution analysis of biological samples of complex matrix and history.