Development and Applications of a Fundamental Parameter Method for X-ray Fluorescence Analysis

The fundamental parameter (FP) method allows calculation of X-ray intensities theoretically and is used in various aspects of X-ray fluorescence (XRF) quantitative analysis. Wavelength dispersive X-ray fluorescence (WDXRF) spectrometers capable of performing the FP method were first developed in the late 1980s by Japanese manufacturers Rigaku and Shimadzu. Since then, through broadening of features including application to energy dispersive X-ray fluorescence (EDXRF) spectrometers and continuous improvements, it is now commonly used in various fields. The FP method is not only used for standardless analysis allowing quantification without type standards, but also for the analysis of coating and thin film thicknesses. It has also been adopted by JIS and ISO standard test methods of various materials as a method to calculate the matrix correction coefficients applied to the conventional calibration equation. FP method incorporating scattering X-ray intensities has also been developed for the analysis of polymers and biological samples and is also beneficial for the analysis of irregularly shaped samples. The authors recognize that the FP methods developed by the authors and their groups greatly contributed to the expansion of applications of X-ray fluorescence analysis.