Certification of NIST SRM 1961: 30 μm Diameter Polystyrene Spheres

Area of Science:

• Materials Science
• Metrology
• Particle Characterization

Background:

• Accurate particle size determination is crucial for various scientific and industrial applications.
• Standard Reference Materials (SRMs) provide essential traceability for measurement results.
• NIST Standard Reference Material 1961 was developed to address the need for a certified particle diameter standard.

Purpose of the Study:

• To certify NIST Standard Reference Material 1961 for particle diameter.
• To establish a reliable standard for monosize polystyrene spheres in aqueous suspension.
• To provide traceable measurements for particle size analysis.

Main Methods:

• Primary method: Optical microscopy for measuring the diameter of over 2000 monosize polystyrene spheres.
• Supporting method: Electron microscopy for independent verification of particle diameter.
• Statistical analysis of size distribution using mean diameter and standard deviation.

Main Results:

• Certification of SRM 1961 with a mean particle diameter of 30 μm.
• Optical microscopy yielded a mean diameter of [Formula: see text] μm with a standard deviation (σ) of 0.21 μm.
• Electron microscopy provided supporting data for the certified diameter value.

Conclusions:

• SRM 1961 is certified for particle diameter, providing a reliable standard for calibration.
• The combination of optical and electron microscopy ensures high confidence in the certified value.
• This certified material supports accurate particle size measurements in diverse applications.