Determination of trace elements in Mycobacterium fortuitum by x‐ray fluorescence spectrometry

Using energy‐dispersive x‐ray fluorescence analysis with an ¹²⁵I ring source, it was possible to determine the concentration of several elements, such as Mn, Fe, Cu, Zn, Br, Rb and Sr, at the µg g^?1 level in a microorganism (Mycobacterium fortuitum) and in nutrient medium. It was observed that the bacteria always incorporated a fixed amount of a given element even if the concentration in the nutrient medium was different. It was possible to contaminate the cells also with Zr. The sample preparation and irradiation process developed is a non‐destructive microorganism analytical method, as about 70% of the bacteria survived the measuring process. Copyright © 2003 John Wiley & Sons, Ltd.