This article discusses the application of an LS13 320 instrument to provide an automated solution to a customer that uses the dry powder sieving method. The use of the LS13 320 with the Tornado Dry Powder System (Figure 1) enables the customer to shorten processing time, improve reproducibility and accuracy, and achieve better overall QC process.
Figure 1. LS 13 320 with Tornado Module. Image credit: Beckman Coulter
Sieving or Gradation Method
The sieving method has been traditionally used for dry particle size analysis to determine the performance of materials during applications. Any type of organic and non-organic materials can be analyzed using the sieving method, including soils, coal, feldspars, granite, clays, crushed rock, sands, seeds, grains, and a wide variety of manufactured powders. The following are the drawbacks of the dry powder sieving method:
- Results are influenced by environmental factors such as vibration, dust and noise
- Laborious sample and equipment preparation
- Manual data processing
- Results vary from operator to operator
- Size resolution is only 4-6 data points
- Poor accuracy and precision
- Random bias from the particle shape leads to inferior R & R
- Poor accuracy of the measurement integrity
All these issues can be addressed using the Beckman Coulter LS 13 320 Laser Diffraction method.
Advantages of the LS 13 320 Laser Diffraction Method
The following are the advantages of the LS 13 320 Laser Diffraction method:
- Less environmental impact, which means low noise operation that is free from vibration and dust
- Minimal instrument setup
- Little or no sample preparation
- Measurements can be taken within seconds
- Sample volume is much lower than that that of the sieving method (Figures 2 and 3)
Figure 2. Sieve Pans - Minimum sample amount is typically 100 grams. Image credit: Beckman Coulter
Figure 3. LS13320 sample vials - Sample amount is typically 35cc. Image credit: Beckman Coulter
It is possible to directly correlate the historical sieving data of the customer to the LS13 320 Laser Diffraction results (Figure 4).
Figure 4. Correlation Graph LS 13 320 to historical Sieve data. Image credit: Beckman Coulter
Steps Involved in the Dry Powder Sieving Method
The following are the steps involved in the dry powder sieving method:
Step 1 – The sieves are cleaned to ensure the removal of traces of previously analyzed sample.
Step 2 – The sieves are weighed individually before the analysis.
Step 3 – The information is entered manually.
Step 4 – The sieves are then stacked (Figure 5).
Figure 5. Typical Sieve stack. Image credit: Beckman Coulter
Step 5 – The next step is sample preparation. The sample material is dried, weighed and loaded into the sieves.
Step 6 – The test is run on the material.
Step 7 – This step involves manual data retrieval and processing, which include:
- The sieves are weighed post process
- The data is entered manually, analyzed and processed
- Determining pass/fail
- Sieve cleanup
For the sieving method, the requirement of broad acceptance criteria due to the influence of shape could lead up to a 50% error.
Reduced Process Steps with the LS 13 320
After configuring the device with the standard operating process (SOP) customized for a specific product, the following are the minimum steps needed for the customer to shift from the sieving method to the laser diffraction method:
Step 1 – The SOP is loaded. This loading can be done electronically to multiple sites to have a constant QC process across the business platforms.
Step 2 – The sample is loaded into the measurement vessel.
Step 3 – The SOP is started and the results will be delivered within seconds in the desired format. It is possible to store the data for archiving and trend analysis, and present it in many different statistical and graphical formats. This feature demonstrates the accuracy and precision of the LS13 320 system.
The Beckman Coulter LS13 320 Laser Diffraction system is able to accurately quantify and correlate the historical sieving data of the customer, with almost a 100 more measurement points. This article showed a practical method to shift from a manual sieving process to an automated process using the LS13 320, with additional benefits such as reliability, accuracy, repeatability, low environmental impact, and reduced processing time. Moreover, operators of all skill levels can handle this modern method, thanks to a single push button measurement.
This information has been sourced, reviewed and adapted from materials provided by Beckman Coulter, Inc. - Particle Characterization.
For more information on this source, please visit Beckman Coulter, Inc. - Particle Characterization.