Wet Sample Preparation for Laser Particle Size Analyzer – Part 1
2025-10-21Bettersizer
Before You Start
- Always check the Safety Data Sheet for solubility, reactivity, and compatibility.
- Ensure good ventilation when using volatile or flammable solvents, such as Isopropyl Alcohol (IPA), ethanol, etc.
- Enter refractive index and absorption of the particle material in the software.
Choosing the Dispersion Medium
|
Sample type |
Recommended medium |
Notes |
|
Hydrophilic |
Deionized water |
May add a small amount of non-ionic/anionic surfactant |
|
Slightly hydrophobic |
IPA, ethanol, or water + 10–50% IPA |
Often stable without extra surfactant |
|
Strongly hydrophobic |
IPA/ethanol + PVP;N-Methyl-2-pyrrolidon (NMP)；mineral oil |
NMP only for corrosion-resistant flow paths; always clean thoroughly |
Adding Dispersant
- When? Only if solvent + stirring still shows agglomeration.
- Common dispersants (add directly to the bath, final concentration w/w):
-Tween 80 (nonionic): 0.05%
-Sodium Dodecyl Sulfate (SDS) (anionic): 0.02%
-PVP (polymer): 0.10% - Additional dispersing aids (prepare stock solutions first): Make a 2% aqueous stock solution of SMP (sodium hexametaphosphate) or TSPP (tetrasodium pyrophosphate), then add from stock to reach 0.02–0.10% active concentration in the test bath.
Stirring and Sonication
- Stir for 1–3 min.
- Sonicate for 1 min if needed, repeat only with cooling intervals.
- Goal: break agglomerates without damaging particles.
General recommendation only. Please consult Bettersize for special solvents or corrosion-resistant configurations.
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