Optimizing your method development is key to obtaining accurate particle-sizing results with laser diffraction. However, ensuring that every standard operating procedure (SOP) is flawless can be challenging.
SOP Architect on the Mastersizer 3000+ addresses this issue by walking you through every step of method development. This tool helps minimize the risk of straying from best practices, resulting in standardized, more reliable methods that are created efficiently with minimal supervision.
Eliminating Errors in Method Development
Anyone involved in method development for laser diffraction has likely faced this scenario: you are working with a new sample type, uncertain about how to proceed on a specific point, and the expert who could help is unavailable. You might have some documentation that could assist, but with time constraints, you are left wondering if your best guess is truly the best solution.
This is precisely the challenge that SOP Architect on the Mastersizer 3000+ is designed to overcome. By guiding you interactively through the ideal workflow for method development, and offering prompts and expert advice at each step, it enables users to create SOPs that adhere to best practices—whether they are new to the process or a seasoned professional.
About the Mastersizer 3000+
Since its introduction in 2012, the Mastersizer 3000 laser diffraction system has earned a well-deserved reputation as a high-performance, adaptable, and compact device for determining particle size distributions.
The Mastersizer 3000 has become a significant tool in R&D and manufacturing, with applications ranging from checking powder flowability and packing to understanding medicine dissolving rates, monitoring food emulsion stability, and guaranteeing optical paint performance.
This success is due to both hardware and software. In addition to numerous features and accessories, Malvern Panalytical has released two software modules over the years that benefit all Malvern instruments: Smart Manager for optimizing uptime and usage and OmniTrust for ensuring regulatory compliance and data integrity.
The Mastersizer 3000+, released in March 2024, continues this tradition with three new software tools to help users improve their particle-sizing capabilities and assist key decision-making:
- SOP Architect for standardizing and streamlining method development.
- Improve confidence in routine measurements and technique development with Size Sure.
- Use Data Quality Guidance for independent decision-making on real-world samples.
With the instrument’s flexibility and ease of use, the Mastersizer 3000+ stands out as the premier choice for particle sizing.
SOP Architect for the Mastersizer 3000+
With its on-screen prompts and guidance links, SOP Architect assists users in avoiding common pitfalls during method development, such as adapting previous methods or overly relying on internal documentation.
This makes it an ideal tool for individuals who are not yet fully confident in the method development process or the associated decision-making, while also serving as a valuable refresher for more experienced professionals. SOP Architect clarifies every stage of the method development workflow by guiding users through five distinct phases.
Stage 1: Sample and Material Details
The SOP Architect process begins by requesting users to enter basic details such as sample name, material identity, particle type, refractive index, and absorption index (see Figure 1).
Figure 1. An example of input screens for sample and material details on SOP Architect. Image Credit: Malvern Panalytical
Users can also choose which tests to perform. While beginners may opt for all available tests, more experienced users might prefer to customize the stages based on their specific needs.
Additionally, the software will prompt users to select the appropriate dispersant through a beaker test, providing guidance via videos and step-by-step instructions—resources particularly valuable for those new to laser diffraction.
Stage 2: Stability Checks
At this stage of method development, SOP Architect evaluates the stability of the sample over time using default conditions that are appropriate for most sample types.
Initially, the system conducts a series of six measurements on a single aliquot. The software then analyzes trends in obscuration, cumulative volume distributions (Dv10/50/90), and total scattering data to detect significant sample changes such as agglomeration, dispersion, or dissolution.
Following this analysis, it provides an assessment of the likelihood of any issues and offers links to guidance on the best course of action (see Figure 2).
Figure 2. An example of a stability check report generated using SOP Architect, showing a sample that may be agglomerating. Image Credit: Malvern Panalytical
Stage 3: Stir Speed Titration
This stage focuses on optimizing the stirrer speed to get data that accurately reflects the true nature of the particles under investigation. For example, dense or big particles may settle out at too low speeds, whereas emulsions may experience particle shearing at too high speeds.
SOP Architect automatically runs six measurements at each of the following speeds:
- Standard speeds: 1500, 2000, 2500, 3000, and 3400 RPM
- Emulsion: 1200, 1300, 1400, 1500, 1600, and 1700 RPM
The recommended obscuration for the sample at this stage is dictated by whether the estimated particle size is larger than or less than 1 µm. If the expected particle size is unknown, a default value is applied.
With the acquired data, the system compares particle size to stirrer speed and automatically determines the region with the best stable results. Within this range, the stir speed with the least standard deviation is recommended (Figure 3).
Figure 3. An example of a stir speed titration performed using SOP Architect. Image Credit: Malvern Panalytical
Stage 4: Obscuration Titration
In wet tests, the concentration of the particles under test must be carefully regulated, and a reasonable proxy measurement for this is the degree to which the suspended particles obscure the laser beam, which is the focus of the second titration.
In traditional method development, this is a relatively 'manual' process, but with SOP Architect, you get prompts and advice every step of the way.
Five measurements are usually taken for each of six rising concentrations, chosen to fall between six obscuration ranges: 2-3, 4-5, 7-9, 10-12, 15-17, and 19-21 %.
Another advantage of SOP Architect is that it minimizes the number of obscuration ranges evaluated when multiple scattering is found, saving time, samples, and money.
A difficult problem for novices is getting the concentration of each aliquot to fall within the needed range, but with SOP Architect, the program provides both the present obscuration and what you need to achieve, allowing you to get it properly the first time (Figure 4).
Figure 4. An example of an obscuration titration using SOP Architect, showing the current and desired obscuration values. A similar interface is used for the stir speed titration. Image Credit: Malvern Panalytical
Stage 5: Method Repeatability
The final step in method development with SOP Architect is to determine the method's repeatability, which is a reliable indicator of overall data quality. The software encourages you to do three sets of six measurements, each with a new aliquot.
Each data set is run through the RSD variability assessment algorithms developed in Mastersizer 3000+'s Data Quality Guidance module and compared to ISO 13320:2020 and USP variability criteria (Figure 5).
If you receive an unexpected result (for example, if an aliquot fails), the software will walk you through the appropriate procedures, allowing you to improve your method development technique.
Figure 5. Example of Method repeatability report generated using SOP Architect, showing the red headers that appear when an aliquot fails a check, and the green headers that appear when it passes. Expanding each header shows further information, including the Dv10, Dv50 and Dv90 values, and the RSD. Image Credit: Malvern Panalytical
Conclusion
With its structured processes and supportive guidance, SOP Architect provides significant benefits for those new to laser diffraction. For experienced users, having best practices integrated into the software—rather than relying on memory—helps minimize the risk of unnoticed errors and the subsequent impact on data quality.
SOP Architect also integrates seamlessly into the SOP software ecosystem of the Mastersizer 3000+, which is especially valuable for tasks that require consistent method repetition, such as in regulated environments. Methods created with SOP Architect use Malvern Panalytical’s '.sop' file format, ensuring compatibility with SOP Player for execution and SOP Editor for modifications.
In summary, using SOP Architect with Mastersizer 3000+ will allow you to:
- Standardize or simplify method development.
- Embed best-practice in method development and thus achieve consistently high standards.
- Reduce reliance on person-to-person knowledge transfer.
- Incorporate Malvern Panalytical’s experience into your workflow.
- Boost team independence with decision-making.
- Move towards automation of your laser diffraction measurements with SOP Player.
This information has been sourced, reviewed and adapted from materials provided by Malvern Panalytical.
For more information on this source, please visit Malvern Panalytical.