Gentle resuspension
Recover a representative sample without introducing bubbles.
Preparation sequence
A controlled dilution is a measurement process
- Inspect the bottle, lot, expiration and storage history.
- Define the target concentration, final volume and allowable uncertainty.
- Measure a clean diluent blank.
- Resuspend the stock using the approved method.
- Use calibrated volumetric equipment within its practical range.
- Mix the prepared suspension and define hold time.
- Verify concentration or performance when required.
Dispersion controls
Prevent settling and agglomeration from rewriting the result
Validated sonication
Use only when supported; excessive energy can heat, contaminate or alter the system.
Surfactant compatibility
Do not add surfactant casually; it changes chemistry and may affect optics or process compatibility.
Timing
Control the interval between mixing, transfer and measurement.
Serial dilution
Each step adds uncertainty and contamination risk
Serial dilution may be necessary when the required dilution factor exceeds practical pipetting capability. Every transfer adds volumetric uncertainty, adsorption opportunity and contamination exposure.
| Risk | Control |
|---|---|
| Very small stock volume | Use an intermediate dilution with calibrated devices |
| Low final count | Characterize the blank and container contribution |
| Settling | Mix before each transfer and control elapsed time |
| Carryover | Use cleaned or dedicated equipment and blanks |
| Math or unit error | Independent calculation check and documented worksheet |
Method ownership
The calculator does not validate the procedure
Use the mathematical output as one input. The laboratory must validate the complete dilution and measurement method, including uncertainty and recovery.
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.