Determination of the selenium content of soils is an important issue from the viewpoint of environmental and earth sciences. The work presents a lot of technical difficulties due to low concentrations within complex matrices. Dr. E. Margui (Institute of Earth Sciences "Jaume Almera", CSIC, Spain) and her colleagues have recently explored the possibilities of several analytical approaches combined with total reflection X-ray (TXRF) spectrometry. While direct analysis of a solid suspension has a relatively poor detection limit of around 1 mg/kg, a dispersive liquid-liquid microextraction procedure (DLLME) before the TXRF analysis of the soil digest provides much greater detection power. The detection limit is 0.05 mg/kg, which is comparable to or lower than previously published results. For more information, see the paper, "Analytical Possibilities of Total Reflection X-ray Spectrometry (TXRF) for Trace Selenium Determination in Soils", E. Margui et al., Anal. Chem., 82, 7744 (2010).
