UNCERTAINTY OF ATOMIC-ABSORPTION SPECTROMETRY - APPLICATION TO THE DETERMINATION OF LEAD IN BLOOD

The major sources of uncertainty of a method for determination of Pb i n whole blood by atomic absorption spectrometry were identified. The c ombined uncertainty was compared to the experimentally determined vari ation and a satisfactory agreement was found, indicating that no signi ficant sources of uncertainty have been overlooked and that the method is in a state of statistical control. The findings suggest that the m ajor source of uncertainty at low concentrations are random fluctuatio ns (noise) of the atomic signal. Therefore, if improvement of the meth od performance is needed, only actions directed towards enhancing the signal-to-noise ratio are suitable.