Particle size distribution by space or time-dependent extinction profiles obtained by analytical centrifugation concentrated systems
Torsten Detloff, Titus Sobisch, Dietmar Lerche
Powder Technology, Volume 174, Issues 1–2, 2007, Pages 50-55, ISSN 0032-5910, https://doi.org/10.1016/j.powtec.2006.10.021.
(https://www.sciencedirect.com/science/article/pii/S0032591006004529)
Research Topic:
This article discusses the particle sizing capabilities of the LUMiSizer. Particle size results obtained from the LUMiSizer are compared to laser diffraction, dynamic light scattering (photon correlation spectroscopy), and scanning electron microscopy (SEM) particle sizing measurements. Fro mono-modal particle size dispersion, the results agree well. For complex and multimodal distributions, the LUMiSizer has a higher resolution than the other techniques. The LUMiSizer can resolve multimodal distributions where the different technologies often fail. The authors also showed examples for particle sizing for high concentration dispersions.
Keywords: LUMiSizer; particle sizing; concentrated dispersions; laser diffraction; dynamic light scattering; multi-modal particle size distributions; mono-modal particle size distributions
Paper Highlights:
We often get questions that go something like this:
how good is “your “particle sizing?
how does “your” particle sizing compare to laser diffraction particle sizing or dynamic light scattering-based particle sizing?
They are all fair and reasonable questions. I would pose the same questions.
Instead of answering with a simple “pretty good,” we decided to publish some objective, fair, and peer-reviewed data. This paper addresses these questions.
Section 3 and Figure 3 discuss the hindrance function and the optical effects that influence the analysis of high concentration dispersions.
Figure 5 compares the particle size results for a four-modal particle suspension obtained by the LUMiSizer (STEP-Technology®), laser diffraction, and dynamic light scattering techniques. Equal ratios of 280 nm, 550 nm, 750 nm, and 1550 nm silica particles made up the four-modal dispersion. While the LUMiSizer detects all four peaks correctly, laser diffraction and dynamic light scattering technologies did not. The difference is due to different scientific principles and not dependent on the manufacturer. The STEP-Technology takes advantage of both Stoke’s law and light scattering fundamentals.
Figure 7 shows that simple monomodal systems such a dilute silicone oil in water emulsion between laser diffraction and the LUMisIzer are the same.
The remainder of the publication is about particle sizing at high concentrations. By incorporating the correct hindrance function, correct particle sizing at high concentrations is indeed possible.
I understand that high concentration is, of course, a relative term. While we have shown in other work that particle sizing with concentrations as high as 30 percent is readily doable, the maximum examined in this publication was 10 percent. Ten percent may not sound high; however, considering other analytical techniques such as dynamic light scattering or laser diffraction, it is the order of magnitude more concentrated.
