Pressed Pellet
Definition
A sample preparation form in which finely ground, dried soil is mixed with a binder and compressed under several tonnes of pressure into a flat, homogeneous disc for XRF measurement.
- Sample type
- Ground, dried soil mixed with binder
- Preparation
- Compressed under several tonnes of pressure
- Result
- Flat, homogeneous disc
- Used for
- XRF measurement
Common questions
Why does soil need to be pressed into a pellet before XRF analysis?+
XRF measures X-ray fluorescence from a flat, uniform surface, so loose or unevenly packed soil would give inconsistent readings due to particle size and surface irregularities; pressing the ground sample into a dense, flat pellet removes those variables and improves measurement reproducibility.
What happens if the pellet is not homogeneous?+
Uneven particle distribution or incomplete mixing with the binder can leave localized concentration differences across the pellet surface, so the analyzer's measurement spot could give a result unrepresentative of the bulk sample, undermining a like-for-like comparison with a reference soil.
Related terms
- Energy-Dispersive XRF (ED-XRF)
- An XRF configuration using a solid-state detector that registers all emitted photon energies simultaneously. Faster and more compact than WD-XRF, enabling portable...
- Fused Bead
- A preparation method where soil is dissolved in molten lithium tetraborate or metaborate flux at around 1100 degrees Celsius to form a...
- Matrix Effect
- The absorption or enhancement of characteristic X-rays by other elements in the same sample, causing apparent concentrations to deviate from true values...
- Wavelength-Dispersive XRF (WD-XRF)
- An XRF configuration that uses an analysing crystal to separate emitted X-rays by wavelength before detection, giving high spectral resolution and low...
- X-Ray Fluorescence (XRF)
- A technique in which a sample is irradiated with a primary X-ray beam, causing its constituent elements to emit characteristic secondary (fluorescent)...