Density Analysis
Density is defined as mass of a sample or body divided by its volume. This value is typically expressed in kg per m3 or g per cm3 for solids, as well as in g per mL for fluids at a given temperature. Alternately, the dimensionless ratio between a sample density and the density of a reference material, termed specific gravity, may be reported.
Changes in the density of a raw material or product can indicate changes in its structure or composition, which could lead to performative differences. As such, density is an important parameter for product development as well as quality control in many industries ranging from pharmaceutical, food and beverages, cosmetics, agricultural, environmental, plastics, ceramics and industrial building supplies.
There are several types of specialized density terms as utilized by different industries, depending on what constitutes the sample volume. Below are simplified definitions of the different types of voids that may be included or excluded from the sample volume.
• Intraparticle void: the void within each sample piece or granule. The terms below can also be applied to a single sample piece, core, or chunk.
Open pore: pores accessible from the sample surface
Closed pore: pores inaccessible from the sample surface
• Interparticle void: the space between the granules or particles
• External void: roughness or irregularities on the sample surface
PTL can advise on the most appropriate techniques suitable for your needs. We have capabilities for density determination using a variety of techniques. PTL can also follow standard methods from various organizations such as ISO, USP, and ASTM. Listed in the table below are examples of common density types. The void volumes included in the sample volume are marked with an X.
Advantages
- Density is a valued test for variety of other characterizations
- PTL can support standard methods relating to ISO, USP, and ASTM
Considerations
- Differences in defining the sample volume yield the various types of density: Bulk, Tapped, Envelope, True, and Skeletal or Apparent
- Important to align the appropriate type of density with the desired applications
Sample Requirements
Sample quantity varies by technique and method.
Please contact us to share specifics about your sample and density testing type(s) to determine a suggested volume to submit for your analysis.
Detection Range
Varies for each technique.
Data Reported
Density is typically reported in g/cm³ or kg/m³; other units may be used upon request.
Instrumentation
Particle Technology Labs has both Micromeritics AccuPyc II and Anton Paar UltraPyc instrumentation to ensure we find the correct instrumentation for determining True Density of your material.
Envelope Density is completed with the GeoPyc pycnometer.
Bulk and Tap density can be achieved with a graduated cylinder approach, in conjunction with the dual station Anton Paar Autotap, or done via the Freeman FT4 Powder Rheometer.
Micromeritics AccuPyc II
Anton Paar UltraPyc 5000
Micromeritics GeoPyc 1360
