TXRF analysis

What is TXRF analysis used for?

TXRF is primarily used to carry out elemental analysis of sample surfaces, therefore finding numerous applications in fields including materials science and polymer chemistry, where it is used to characterize and investigate the surfaces of newly developed materials. It can also be used for wafer mapping of the elemental composition.

TXRF has applications in metallurgy and similar physical studies to test the composition of metallic and alloy surfaces. It also finds use in geological and environmental sciences for investigating the composition of naturally occurring materials.

How does TXRF work?

TXRF analysis begins by generating a monochromatic X-ray beam, which is directed at the surface of a sample at a very shallow angle, usually less than 0.5° with respect to the plane of the surface. This means that the beam only effectively ‘grazes’ the surface of the sample. As the beam interacts with the atoms on the sample surface, it will cause electrons to move between energy levels. In turn, this will cause them to release distinctive photons of energy in a process called fluorescence. 

The fluoresced photons are picked up by a detector and their respective energies and magnitudes are recorded. The energy of each photon is specific to the element that it was emitted from, and their relative magnitudes reflect the quantities of the element in the sample. Through this, it is possible to determine the precise elemental composition, including elements that are only present in trace amounts. TXRF cannot, however, detect elements with an atomic number below 11.

Suitable samples and sample preparation

TXRF is typically performed on solid samples in the form of very fine powders or thin film depositions. Liquids, solutions, and suspensions can also be analyzed. To do this, a droplet is deposited on a sample plate and dried to form a thin, flat surface. Additional preparation steps, such as dilution, may be required if the sample contains salts or suspended particles, which may induce matrix interference.

TXRF vs XRF

Fundamentally, X-ray fluorescence (XRF) and TXRF work in the same way. The difference arises as the TXRF setup is designed specifically to reduce the amount of scattered and absorbed X-rays, instead maximizing the amount of fluorescence. This in turn produces a very high signal-to-noise ratio and allows the technique to have a far higher sensitivity than conventional XRF. This means it can detect elements in trace quantities, which is amplified by its ability to focus on extremely small sections of the sample, ultimately providing more in-depth analysis.