Some aspects of statistical distribution of trace element concentrations in biomedical samples

Concentrations of trace elements in biomedical samples were studied using S -ray fluorescence (XRF), total reflection X-ray fluorescence (TRXRF) and pa rticle-induced X-ray emission (PINE) methods, Used analytical methods were compared in terms of their detection limits and applicability for studying the trace elements in large populations of biomedical samples. In a result, the XRF and TRXRF methods were selected to be used for the trace element c oncentration measurements in the urine and woman full-term placenta samples . The measured trace element concentration distributions were found to be s trongly asymmetric and described by the logarithmic-normal distribution. Su ch a distribution is expected for the random sequential process, which real istically models a level of tract elements in studied biomedical samples. T he importance and consequences of this finding are discussed, especially in the context of comparison of the concentration measurements in different p opulations of biomedical samples. (C) 1999 Elsevier Science B.V. All rights reserved.