Theoretical evaluation of solid sampling electrothermal atomic absorption spectrometry for screening purposes

Obtaining results in the determination of metals by electrothermal atomic a bsorption spectrometry is conditioned by the non-homogeneity of the sample and the possible appearance of outliers, which make it difficult to obtain reliable results with only a few measurements. In order to establish the op timum conditions for using the technique as a screening method, 18 000 resu lts corresponding to different possible situations were simulated by comput er and subsequently analysed using information theory. In view of the resul ts obtained, it can generally be claimed that the median can be used to bet ter effect than the mean value as the former is less affected by the potent ial presence of outliers. Using the median and with normal working conditio ns, the minimum number of measurements that need to be carried out to guara ntee a recall of over 0.95 in a screening method ranges from 5 to 20, invol ving between 15 min and I h work.