LimsPulse
Particle & solid-state

X-ray powder diffractometer (XRPD)

Directs X-rays at a powder and records the angles at which they are diffracted by the crystal lattice. The pattern is a fingerprint of the crystal form, used to identify polymorphs, salts and hydrates and to detect amorphous content.

  • Pharmaceutical
  • Minerals & mining
  • Cement & construction
  • Materials science
  • Chemicals
  • Forensics
Photo of a X-ray powder diffractometer (XRPD)
Photo: René Volfík, CC BY-SA 4.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the instrument is calibrated (silicon check within date) and the radiation warning lights work.
  2. 2Wear your dosimeter badge if your site requires it.
  3. 3Check cooling water or chiller is running for the X-ray tube.
  • Never defeat a door interlock.
STAGE 2

Sample preparation

  1. 1If needed, gently break up lumps with a spatula or a light grind; avoid heavy grinding, which can change the form.
  2. 2Fill the holder and level the surface flush with the holder rim using a glass slide, without pressing hard.
  3. 3For small amounts use a zero-background silicon plate.
  • Sample height errors shift peak positions; the surface must be flat and level with the reference plane.
STAGE 3

Measurement

  1. 1Load the holder and close the enclosure door.
  2. 2Select the approved method (e.g. Cu Kα, 40 kV / 40 mA, 2–40° 2θ, defined step size and time per step, spinning on).
  3. 3Run the reference standard or reference form if the method requires it, then the samples.
  4. 4Ramp the generator down to standby after the run, as per site practice.
STAGE 4

Evaluation

  1. 1Overlay the sample pattern with the reference pattern of the specified form.
  2. 2Check that characteristic peaks of the specified form are present and those of other forms are absent.
  3. 3Report peak positions and the conclusion; record any extra peaks for investigation.
  • Compare positions first; intensities can vary with orientation and particle size.
In LimsPulse · Calibration Management

Keep every XRPD in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how