Optimisation of the drying method during sample preparation for total reflection X-ray fluorescence measurements using acid digested biological reference materials

Sample processing is one of the key steps in the analysis by the Total Reflection X-ray Fluorescence (TXRF) method. However, the preparation of the sample itself for measurement can present many difficulties and introduce many errors visible in the measurement results. In this work, we have attempted to verify whether, in the case of biological specimens, such an effect can be caused by the applied sample drying procedure. For this purpose samples of four reference materials - apple leaves, tomato leaves, oyster tissue and beef liver, were acid digested. Ten replicates were prepared for each reference material and dried using five methods: laminar flow chamber (LFC), 100 mbar vacuum chamber (VC), 250 W infrared lamp (IR) and hot-plate with the use of two heating temperatures i.e. 45 °C and 75 °C (HP45, HP75). The results showed that, in the context of measuring a multi-element sample, the choice of drying method has no significant effect on the final TXRF quantitative results.