Non-Linear Effects in TXRF Spectroscopy: New Study Evaluates Dead Time

In a recent study, researcher Leonardo Bennun investigated the non-linear effects in total reflection X-ray fluorescence (TXRF) spectroscopy (1). TXRF is a widely used analytical technique that has high sensitivity and selectivity for trace element analysis. However, TXRF does have a key limitation that the study commented on: its upper limit of linear response can lead to nonlinear distortions in spectra that may affect the accuracy of measurements (1).

The study focused on the influence of the amount of sample in non-linear effects in TXRF (1). The research team conducted an experimental sequence on "ad-hoc"-made samples obtained from a pre-established serial dilution (1). They acquired spectra in high, medium, and low counts to evaluate the non-linear effects sequentially as a function of the sample amount (1).

The study found that the main sources of non-linear effects are the matrix effects and the dead time (1). For the simple inorganic samples studied, the dead time effect proved to be more important than the matrix effects (1). Dead time is defined as the time that a detector or electronic system cannot receive and process additional signals after detecting a signal. A mathematical methodology was developed to evaluate the dead time effects; it ended up being unpredictable and irreversible, with values at approximately 10% for the samples analyzed (1).

The results of the study have important implications for using TXRF spectroscopy in trace element analysis (1). According to Bennun, "some usually accepted TXRF characteristics could be re-evaluated, like the 5 orders of magnitude of dynamic range” (1). In addition, the study suggests that the amount of analyzed specimen should be carefully evaluated before measurements are made to avoid dead time effects (1).

This research contributes to improving the accuracy and reliability of TXRF spectroscopy in trace element analysis by providing a better understanding of the non-linear effects and their sources. Bennun's work highlights the importance of evaluating the dead time effect, which should be taken into account in the development of new analytical procedures and in the interpretation of TXRF spectra (1).

Overall, the study provides a procedure for the evaluation of the dead time effect and highlights the importance of careful consideration of non-linear effects in TXRF spectroscopy (1). The findings of the study will be of interest to researchers and practitioners in the field of analytical chemistry and materials science.

Reference

(1) Bennun, L. Non linear effects in TXRF spectroscopy. A procedure for the evaluation of the dead time. Spectrochim. Acta. Part B At. Spectrosc. 2023, 203, 106652. DOI: 10.1016/j.sab.2023.106652