Settling
Larger particles can settle more rapidly; mixing and elapsed time must be controlled.
Current family profile
Approximately 1–160 µm aqueous PSL standards
| Attribute | Current Applied Physics family-level description |
|---|---|
| Material | Polystyrene latex spheres in aqueous suspension |
| Nominal range | Approximately 1–160 µm |
| Common bottle volume | 15 mL on the current family page |
| Density | Approximately 1.05 g/cm³ |
| Refractive index | Approximately 1.59 at 589 nm and 25°C |
| Suggested storage | 2–8°C on the current family page |
| Documentation | Lot-specific size, uncertainty and physical-property information |
Large-particle behavior
Settling and sampling become more visible
Sampling geometry
Bottle, transfer device, tubing and sample-cell geometry can bias recovery.
Method selection
Optical microscopy, resistance methods or light extinction may be relevant depending on size and procedure.
Concentration
A convenient stock concentration may still require validated dilution or count control.
Applications
Where larger PSL nodes are used
- Light-extinction liquid particle-counter calibration and verification.
- Optical microscopy and image-analysis checks.
- Pharmaceutical and laboratory particle-counting applications.
- Flow-imaging and research methods when PSL is an appropriate surrogate.
- Instrument linearity or response checks across multiple size nodes.
Fit-for-purpose warning
Spherical PSL may not mimic irregular or low-contrast process particles
PSL provides a repeatable spherical reference. It may not reproduce the morphology, transparency or refractive index of protein aggregates, fibers, glass or process debris. Interpret the result as the procedure defines it.
Applied Physics technical pathway
Match the standard to the measurement—not the other way around.
Send the instrument, medium, target size, concentration, certificate and packaging requirements to Applied Physics for a technical recommendation.