Bulk sample measurement: Tablet

Powder X-ray diffractometers can readily measure bulk samples if techniques are devised for sample preparation, and measurement conditions are properly set. When measuring samples which have curved surfaces, such as pharmaceutical tablets and ball bearings, various effects are seen due to the curvature, such as shifting of the diffraction angle and widening of the full width at half maximum. In the case of samples with these kinds of surfaces, adjustment is done using clay or cellophane tape from the back side of the aluminum sample plate, so that the sample surface is at the same height as the reference surface of the sample plate. The effects of curvature can be reduced by performing the measurement while narrowing the divergence slit and the incident height-limiting slit. Fig. 1 shows the X-ray diffraction pattern and qualitative analysis results for a pharmaceutical tablet. As a result of measurement, it was possible to identify the active ingredients in the tablet as ibuprofen and ethenzamide.

Fig. 1: X-ray diffraction patterns of pharmaceutical tablets

Apparatus condition:

MiniFlex600 (F.F tube 40 kV, 15mA), Detector: D/teX Ultra, Slit conditions: DS = 0.1 mm, SS = 8 mm, RS = 13 mm, Incident side and receiving side Soller slit: 2.5°, Incident height limiting slit = 2 mm

Measurement condition:

Scan range: 2θ = 3 ~ 40°, Step width: 0.02°, Scan speed: 4° / min. (about 10 min.)

New sixth generation MiniFlex X-ray diffractometer (XRD) is a multipurpose analytical instrument that can determine: phase identification and quantification, percent (%) crystallinity, crystallite size and strain, lattice parameter refinement, Rietveld refinement, and molecular structure. It is widely used in research, especially in material science and chemistry, as well as in industry for research and quality control. It is the newest addition to MiniFlex series of benchtop X-ray diffraction analyzers from Rigaku, which began with the introduction of the original MiniFlex system decades ago. Read more...

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