Total Reflection X-Ray Fluorescence Analysis Under Various Experimental Conditions

Total reflection x-ray fluorescence (TXRF) is a well established analytical technique which excels in the deter-mination of trace elements in liquid samples with extremely low detection limits. In TXRF analysis, the use of different techniques to modify the excitation energy spectrum and to collimate the x-ray beams has been reported in the past. All these techniques require that the alignment of the TXRF set-up is optimized in order to obtain the maximum ratio between fluorescence signals and background, i.e., the lowest detection limit. Owing to the fact that total reflection conditions demand very small incident angles (a few mrad), the alignment of the spectrometer and further optimization of the geometry proved to be difficult and time consuming. In order to overcome these difficulties, a TXRF spectrometer with computer-assisted control of the reflector position which is capable of being configured for different experimental conditions was constructed. In this paper, the spectrometer was used to compare the effect that different spectrum modification techniques have on the sensitivity and detection limits of different intermediate-Z elements.