![]() ![]() ![]() Hint: It is because clay particles are platy and not spherical, as assumed by laser diffraction. They describe and explain these differences for the clay fraction in VERY well-researched detail. As for the discrepancies in the clay fraction, a seminal paper published by Konert & Vandenberghe in 1997 in the journal Sedimentology compared laser diffraction with the pipette and sieve methods. W e would also like to note that the results regarding approximately 10 % uncertainty in the particle size for the > 10 µm particles was to be expected : A ll instruments are laser diffraction based, so they should all show roughly the same results. The differences really are striking, and it is absolutely something to be aware of for any particle size application. This is the first time we here at Sequ oia has seen a study that looks at the effect of ultrasound between different ultrasonic devices. concludes that results from different laser particle sizers should not be directly compared when ultrasound is used. However, the effect of ultrasonic treatment yielded curious results: Data from the Beckman Coulter showed absolutely no effect from sonification (d50 was unchanged), while data from the three others showed d50 decreasing to varying degrees – sometimes by more than 50 %. No instrument particular ly stood out as generally better or worse regarding these aspects. silt or sand) was missing and did not ‘create’ particles in that particular size class. All devices accurately characterized samples where any size class (e.g. Also observed was a higher relative difference between the real and observed clay fraction when the clay proportion was lower than ~10 %. They found that none of the devices accurately characterized clay (this is well-known for all laser diffraction instruments). However, for samples mostly characterized by clay and fine silt particles, the d50 was overestimated by 6-68 %. found that all instruments estimated the median diameter (d50) for particle-sizes above 10 µm within 10 % uncertainty. Measurements were performed on a set of standardized samples created from certified reference materials (CRM) and sediment samples from the Rhone River, France.įor the size distribution and the proportion of clay, silt and sand, Lepage et al. the effect of using ultrasound on a sample in order to disperse it. ![]() Th is paper compares Sequoia’s LISST-Portable|XR with three other commercially available laser particle sizers frequently used for laboratory work: A Beckman Coulter LS 13,320 a Cilas 1190L and a Malvern MasterSizer 2000. But you probably shouldn’t compare data from different instruments if you used ultrasound for particle dispersion. Tl dr: No instrument in particular stood out as better or worse. January’s featured paper is here! Lepage H, Masson M, Delanghe D, Le Bescond C (2019): Grain Size Analyzers: Results of an I ntercomparison Study. LISST-Portable|XR Comparison with Beckman Coulter, Cilas, and Malvern Particle Sizers ![]()
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