Quantitative X-ray fluorescence analysis of solutions

Principle

Various solutions, with known element concentrations, are subjected to polychromatic X-rays. The energy and intensity of the resulting fluorescence radiation of the dissolved elements are analysed with the aid of a semiconductor detector and a multichannel analyser. In order to determine the unknown element concentrations in the solutions, calibration is performed. For this purpose, the known element concentrations of the calibration solution are plotted against the corresponding fluorescence intensities of the dissolved elements.

Tasks

1. Calibrate the semiconductor energy detector with the aid of the characteristic radiation of the tungsten X-ray tube.
2. Record the fluorescence spectra of potassium bromide solutions with various concentration levels.
3. Determine the intensity of the characteristic bromine radiation, based on the spectra.
4. Create a calibration function that is based on the concentration values as well as the intensity of the associated fluorescence radiation.

Learning objectives

• Bremsstrahlung
• characteristic X-radiation
• energy levels
• fluorescent yield
• absorption of X-rays
• Auger effect
• scattering of X-rays
• matrix effects
• solubility
• solubility product
• semiconductor
• energy detectors
• multi-channel analysers