Improvement of a TXRF setup to obtain detection limit in the low ppb range

摘要

To achieve the low ppb detection level a major experimental effort and optimization of the TXRF setup are required. The new solution described in this paper leads to enhancement of the TXRF intensity and to improved signaloise ratio. The adjusted quartz reflector allows control of a reflection angle of a photon beam with respect to the crystal surface with high precision up to 0.006. The installed adjusted diaphragm (followed by the quartz reflector) substantially reduces the level of registered background in the studied range of x-ray energy. The dependence of the x-ray spectra shape, x-ray intensity and detection limit on the diaphragm width and its position on the photon beam as well as on the value of the glancing angle of x-rays from the sample carrier have been studied. The new optimal parameters found result in essential improvement in detection limit equal to similar to 1.0 ppb for elements detected in a liquid sample without any special pre-concentration preparation. Also a very good repeatability of measurements has been reached. Copyright (c) 2006 John Wiley & Sons, Ltd.