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Particle Size Analysis of Micron-Sized Particles Using the Sedimentation Technique

2025-05-16Application Note

This confirms the effectiveness of the BeNano sedimentation method for micron-sized particle size analysis, successfully expanding the size measurement range and application versatility of the DLS analyzer.

Product	BeNano 180 Zeta Max
Industry	Chemicals
Sample	Silicate, PMMA, Alumina
Measurement Type	Particle Size
Measurement Technology	Sedimentation Size Analysis

Introduction

The BeNano 180 Zeta Max, a nanoparticle size and zeta potential analyzer developed by Bettersize, features a photodiode detector positioned at 0° angle. This detector monitors changes in transmitted light intensity over time, allowing for the accurate determination of particle size and size distribution. The sedimentation method utilized in this system provides Stokes diameter measurements, making it well-suited for analyzing particle sizes ranging from a few microns to several tens of microns. This approach effectively addresses the limitations of dynamic light scattering (DLS), which struggles to detect micron-sized particles.

particle size analyzer

BeNano 180 Zeta Max

In this application note, various micron-sized samples were evaluated using the sedimentation method of the BeNano 180 Zeta Max. The obtained results were then compared to size measurements conducted using the laser diffraction (LD) method of the Bettersizer 2600.

Experimental

The BeNano 180 Zeta Max determines particle size by measuring transmitted light intensity and applying Stokes' law.

In order to perform sedimentation particle size analysis, knowledge of the refractive index, density, and viscosity of the dispersant at a given temperature, along with the refractive index, density, and volume of the sample are required.

This study analyzed three types of micron-sized samples: silicate, PMMA, and alumina. Sample densities were measured using the BetterPyc 380 true density analyzer, while D50 values (median diameter) were determined using the Bettersizer 2600 laser diffraction (LD) particle size analyzer.

Table 1. Measured sample information

Sample	Density (g/cm³)
300-mesh Silicate	2.49
320-mesh Silicate	2.49
PMMA-1	1.23
PMMA-2	1.23
PMMA-3	1.23
PMMA-4	1.23
PMMA-5	1.23
Alumina	3.65

For sedimentation-based particle size analysis using the BeNano 180 Zeta Max, the samples were dispersed in water and placed in a 10 mm glass cuvette. Prior to measurement, they were equilibrated at 25°C for 120 seconds. A pipette was used to ensure thorough mixing.

Results and Discussion

Comparison-of-D50-values-from-BeNano-and-Bettersizer-2600

Figure 1. Comparison of D50 values obtained from the sedimentation method of the BeNano and the laser diffraction method.

Table 2. Comparison of D50 values obtained from the sedimentation method of the BeNano and the laser diffraction method.

Sample	Laser Diffraction (μm)	BeNano Sedimentation Method (μm)
300-mesh Silicate	57.42	54.27
320-mesh Silicate	42.99	50.42
PMMA-1	28.56	28.13
PMMA-2	18.55	22.56
PMMA-3	14.98	17.81
PMMA-4	9.556	11.85
PMMA-5	5.447	5.11
Alumina	2.788	3.35

Figure 1 and Table 2 demonstrate that the D50 values obtained using the BeNano sedimentation method closely correspond with those measured through the laser diffraction method for micron-sized samples ranging from 2 μm to 60 μm.