Particle Size Analysis LUM GmbH

Transcription

1 Particle Size Analysis

2 STEP Technology Microparticles LUMiReader Nano- and Microparticles LUMiSizer 2

3 How does it work? Concentration change measured by transmission I 0 I Lambert Beer law Particle size derived from separation velocity way Stokes t 1 t 2 3

4 Features High resolution: you re able to identify small differences in size and multimodal systems No need to assume a specific distribution function Velocity distributions allow to compare samples without knowledge of physical properties Relatively high concentrations can be measured. Multisample measurement (12) Fully complies to ISO

5 How to prepare samples? Ask the customer! (e.g. how to disperse, how to dilute) Dilution only required to minimize hindered sedimentation and multiple scattering Dilute to reach at least 30 % initial transmission Pretest with SOP 1x to check initial transmission Very fast separating particles Use LUMiReader Use continuous phase with higher viscosity e.g. sucrose solution Organic solvents, e.g. petrol, mineral oil Dilute with high viscosity paraffin oil 5

6 How to perform a measurement? LUMiReader Microparticles (500 nm to 300 µm) SOP: 4 d 13 h 39 min 3 s 387p LUMiSizer Nano- and Microparticles (10 nm to 100 µm) SOP: 1d 18h 27m 30s 148p *Please stop measurement if all particles are separated. There is no need to wait too long. 6

7 Particles must sediment or cream to determine the velocity or particle size distribution Very small particles and/or low density difference may lead to long measurement times Measure up to 12 different samples simultaneously (e.g. suspensions and emulsions, aqueous and non-aqueous samples) 20 minutes for one sample measured with other particle size equipment takes 4 hours for 12 samples Optimal measurement conditions at lower temperature (e.g. 4 C) To prevent instabilities during sedimentation / creaming for some samples Very fast separating particles Use RPM ramp Notes Increasing viscosity of continuous phase 7

8 How to do the analysis? - Distribution Type Distribution Type depends on: Customer s aim and material data available Velocity Distribution Direct measurement no calibration / no material properties Information directly related to separation processes Integral measure of size, density difference and media viscosity Ideal for quality control Qualitative information about particle size distribution (PSD) Intensity Distribution Quantitative information about particle size Volume / Number Distribution Quantitative information about particle size and volume fraction of each class Comparison with other measurement methods possible 8

9 How to do the analysis? Analysis Mode Constant Position (Standard Method) Particle size distributions are calculated from time course of transmission at freely selectable positions within the sample For samples with narrow and broad distribution Suspensions: 3 nodes at 123 mm, 125 mm and 127 mm, 1 mm span Emulsions: 3 nodes at 109 mm, 111 mm and 113 mm, 1 mm span Constant Time (only LUMiSizer) Particle size distributions are calculated from transmission profiles along the sample at freely selectable times For narrowly distributed samples To determine the composition in the supernatant during centrifugation e.g. to determine the cutoff size for process centrifuges Multicomponent Samples: How to analyze each component individually? Select appropriate amount of profiles for each component in Constant Position or Constant Time 9

10 How to do the analysis? Material Data SEPView 6 database: currently 102 materials (18 continuous, 84 dispersed) Books: Landolt-Börnstein CRC Handbook of Chemistry and Physics Internet: solvdb.ncms.org/solvdb.htm Educational Resources Material: Refractive Index

11 References T. Detloff: Proof of principle: Does the result of the LUMiSizer / LUMiFuge depend on the used type of sample cells? Dispersion Letters Technical, T1 (2010) 1-2, T. Detloff, D. Lerche, T. Sobisch: Particle size distribution by space or time dependent extinction profiles obtained by analytical centrifugation, Part. Part. Syst. Charact. 23, (2006) T. Detloff, T. Sobisch, D. Lerche: Particle Size Distribution by Space or Time Dependent Extinction Profiles obtained by Analytical Centrifugation (Concentrated Systems), Powder Technology 174 (2007) T. Sobisch, D. Lerche, T. Detloff, M. Beiser, A. Erk: Tracing the centrifugal separation of fine-particle slurries by analytical centrifugation, Filtration 6/4, (2006), Application Notes: Lithium Manganese phosphate Carbon nanotubes Cellulose Dispersions Pulp & Paper Silicone carbide powders Diamond dispersions for CMP (2) Velocity distribution of whey drinks 11