Determination of silicon in organic matrices with grazing-emission X-ray fluorescence spectrometry

The potential of a prototype grazing-emission X-ray fluorescence spectromet er for reliable analysis of sample solutions, obtained by pressurized micro wave oven digestion of Si-spiked organic and biological materials, was inve stigated as part of an inter-laboratory study. The fact that this grazing-e mission technique is based on the total reflection phenomenon and wavelengt h-dispersive detection, gives it the benefit to determine light elements in a sensitive way. Results of the determination of silicon in pork liver, ce llulose, urine, serum, spinach, beer, mineral water and horsetail (dry plan t extract) samples are presented. Some of the results are compared with tho se obtained with other analytical techniques. The study proved that determi nation of silicon traces in biological matrices represents an extremely dif ficult task, however, measurements of silicon are achieved with acceptable precision. The most important problems still arise when sample pre-treatmen t is needed prior to analysis. (C) 1999 Elsevier Science B.V. All rights re served.