Certification of Standard Reference Material 1879b Respirable Cristobalite.

Area of Science:

• Materials Science
• Analytical Chemistry
• Crystallography

Background:

• Standard Reference Materials (SRMs) are crucial for calibrating analytical instruments.
• X-ray powder diffraction (XRPD) is a key technique for material characterization.
• Accurate quantification of crystalline phases like cristobalite is essential for occupational health.

Purpose of the Study:

• To introduce and describe SRM 1879b, a new cristobalite standard for XRPD.
• To provide a reliable calibration standard for quantitative cristobalite analysis.
• To support the National Institute for Occupational Safety and Health (NIOSH) Analytical Method 7500.

Main Methods:

• SRM 1879b was characterized using neutron powder diffraction (time-of-flight and constant-wavelength).
• SRM 676a was employed as an internal standard for phase purity determination.
• Lattice parameters were measured using a custom-built NIST diffractometer.

Main Results:

• SRM 1879b is certified for crystalline phase purity, amorphous phase content, and lattice parameter.
• Neutron diffraction confirmed the high phase purity of the cristobalite material.
• Lattice parameter measurements were performed with advanced instrumentation.

Conclusions:

• SRM 1879b provides a certified standard for accurate cristobalite quantification via XRPD.
• This SRM enhances the reliability of occupational exposure assessments.
• The development of SRM 1879b advances the field of X-ray powder diffraction metrology.