Simultaneous determination of trace elements in serum by energy-dispersive x-ray fluorescence spectrometry

Energy-dispersive x-ray fluorescence is applied in the analysis of human serum to determine the concentrations of several elements simultaneously with minimal manipulation of the sample. The analytical procedure has been developed with standard sera, and standardization, detection limits, and reproducibility have been established. A 50-microL sample of diluted serum, to which an internal standard has been added, is deposited on a thin (4-microns thick) polypropylene film and analyzed by x-ray fluorescence. We report the statistical distributions of the concentrations of Fe, Cu, Zn, and Br obtained in the population (103 samples) studied, and report detection limits for the other 22 elements studied. The simplicity of the method, the high throughput, and the possibility of automating the measurements make this procedure suitable for screening large numbers of sera.