Synchrotron radiation induced TXRF†

The use of synchrotron radiation (SR) as an excitation source for total reflection X-ray fluorescence analysis (TXRF) offers several advantages over X-ray tube excitation. Detection limits in the fg range can be achieved with efficient excitation for low Z as well as high Z elements due to the features of synchrotron radiation and in particular the high brilliance in a wide spectral range and the linear polarization in the orbital plane. SR-TXRF is especially interesting for samples where only small sample masses are available. Lowest detection limits are typically achieved using multilayer monochromators since they exhibit a bandwidth of about 0.01 DE/E. Monochromators with smaller bandwidth like perfect crystals, reduce the intensity, but allow X-ray absorption spectroscopy (XAS) measurements in fluorescence mode for speciation and chemical characterisation at trace levels. SR-TXRF is performed at various synchrotron radiation facilities. An historical overview is presented and recent setups and applications as well as some critical aspects are reviewed.