Determination of copper and iron in human blood serum by energy dispersive x-ray analysis

Human blood serum has been analyzed by X-ray fluorescence spectroscopy utilizing the effect of background reduction by total reflexion of the incident X-ray beam on an optical flat as sample support. For sample preparation a drop of 10 microliter serum was pipetted onto the support and dried to a thin film. The minimum detectable limit was about 1.5 mmol/l in 1000 s and the precision in the 20 mmol/l range of the metals was 3-5%.