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BCR CRM 680 is a newly (year 2001) released reference material consisting of a polyolefinic matrix doped with various metallic compounds in trace concentrations, to be used for calibration of multi-element trace analytical methods. The micro-heterogeneity of CRM 680 was investigated by means of laser ablation inductively coupled plasma spectrometry (LA-ICP-MS) in order to evaluate the suitability of this reference material for calibration of trace-level micro-analytical techniques. The measurements involve an extensive series of local analyses, performed in identical conditions at different locations on the material. Special attention was paid to the proper manner of data selection and normalization in order to eliminate any interdependence or correlation between the data points. The procedure was employed to evaluate the micro-heterogeneity of BCR CRM 680 by calculating the minimal sampling mass. The micro-heterogeneity results obtained with LA-ICP-MS were compared with those obtained by means of synchrotron micro X-ray fluorescence analysis, a non-destructive trace-level micro-analysis technique (m-XRF), and satisfactory agreement between both sets of results was observed. LA-ICP-MS was found to be suitable for the characterization of the micro-heterogeneity of trace metals in polymer reference materials.

A novel semi‐quantitative algebraic reconstruction technique for x‐ray fluorescence tomography data sets is described and its use is demonstrated on laser‐ablated resin samples. The experiments were performed at the ID22 beamline of the European Synchrotron Radiation Facility in Grenoble. The projections were collected using a parallel scheme using 22.5 keV x‐rays at 4 µm resolution. The iterative algebraic reconstruction technique was used to calculate an elemental ‘effective’ concentration distribution. This ‘effective’ concentration is introduced for the first time and allows the attenuation of both the incident x‐ray beam and the fluorescence to be included in the reconstruction procedure. Copyright © 2002 John Wiley & Sons, Ltd.

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