Optimization of TXRF measurements by variable incident angles

Variable incident angles in TXRF instrumentation open up new possibilities in the field of analytical quality assurance of TXRF measurements as well as the possibility of optimizing the measurement angle with respect to the sample carrier. Measurements on the same sample with different incident angles allow a check to be made on the behavior of the internal standard and the elements under investigation within the sample, which makes quantification more reliable, even for difficult samples. This is demonstrated on the example of standard reference material NIST 1633a comparing the relative fluorescence intensities of the elements K, Ti and Fe obtained from a sample prepared from a suspension and a digestion of the SRM material, respectively. Furthermore, it will be shown how the measurement conditions for different sample carrier materials such as quartz and acrylic glass can be optimized by measuring angular-dependent signal and background intensities.