From MicrotracReviewed by Emily MageeDec 18 2024
Can you please introduce yourself and your role at Microtrac?
My name is Serife Korkmaz, and I am the Turbiscan Application Engineer at Microtrac. My role primarily involves supporting our customers in understanding and leveraging the capabilities of the Turbiscan technology for stability measurements. I specialize in colloidal and physical stability, with a strong chemistry background that helps me analyze how particle size, zeta potential, and stability interrelate to optimize formulations and product development.
What key parameters influence colloidal and physical stability, and why are they important?
The key parameters that affect colloidal and physical stability are particle size and zeta potential. Particle size affects properties like solubility, dissolution, and texture, which are crucial for a product's efficacy. Zeta potential, a measure of surface charge, is a critical indicator of colloidal stability, helping prevent aggregation and phase separation. These parameters are essential for delivering stable, high-quality products.
Image Credit: Microtrac
How does Microtrac’s Turbiscan technology assist with stability measurement?
The Turbiscan technology uses static multiple light scattering to monitor stability in real-time without requiring dilution. By scanning samples in a vial from top to bottom, it detects changes in backscattering and transmission, signaling particle size variation or phase separation. This process is significantly faster than visual observation, offering precise stability insights.
What is the Turbiscan Stability Index (TSI), and how does it simplify stability analysis?
The Turbiscan Stability Index (TSI) is an advanced algorithm built into Turbiscan technology that quantifies changes in a sample’s stability over time. It consolidates all detected destabilization phenomena—such as flocculation, sedimentation, and phase separation—into a single numerical value. This value provides a straightforward way to compare and rank the stability of multiple samples.
Turbiscan Stability Index formula. Image Credit: Microtrac
For example, when scanning a sample, the Turbiscan detects variations in light transmission and backscattering as a function of height within the vial. These variations indicate changes in particle distribution, such as sedimentation at the bottom or clarification at the top. The TSI sums up these changes to reflect the overall extent of instability. A lower TSI indicates higher stability, while a higher TSI highlights a less stable formulation.
One of the major advantages of the TSI is its speed. In traditional stability testing, visual observations or manual methods can take weeks or months to identify instability. With the TSI, you can obtain meaningful insights within just a matter of minutes to hours, enabling rapid decision-making during formulation development. Additionally, as it works on native samples without dilution, the measurements are highly reliable and reflective of real-world conditions.
How does Nanotrac Flex measure particle size distribution, and what are its advantages?
The Nanotrac Flex uses dynamic light scattering (DLS) to measure particle size distribution in liquid dispersions. This method relies on the random Brownian motion of particles in suspension. As particles move, they scatter light from a laser source, and the system measures the changes in light intensity over time. Using mathematical algorithms like Fourier transformation, the device calculates the velocity distribution of the particles, which is directly related to their size.
The Nanotrac Flex is particularly versatile because of its unique probe design. This probe contains an optical fiber that transmits the laser beam directly into the sample and collects the scattered light. This setup allows for in-situ measurements, where the probe can be placed directly into the sample vial or even analyze a small drop of liquid. It is a highly practical solution for diverse sample types and settings.
Key advantages include:
- Wide Size Range: It can measure particles from as small as 0.3 nanometers up to 10 microns, making it suitable for a variety of applications.
- High Concentration Capability: Unlike many DLS systems, the Nanotrac Flex can measure samples with concentrations up to 40 % by volume, reducing the need for dilution that might alter the sample’s behavior.
- Speed and Sensitivity: The system provides fast and precise particle size measurements, even in highly turbid or opaque samples.
- Ease of Use: The flexible probe streamlines sample preparation, allowing users to analyze samples directly in their original containers or conduct quick tests with just a small drop of liquid.
Image Credit: Microtrac
What is the underlying principle of Stabino Zeta technology for measuring zeta potential?
Stabino Zeta measures zeta potential through charge separation. A piston oscillates inside a liquid-filled PTFE cup, generating charge movement, which is then detected by electrodes. This setup delivers quick measurements, even for highly concentrated samples, and supports automated titration for pH or salt optimization.
Can you provide an example of how these technologies were used in a real-world application?
In a sunscreen formulation study, we assessed three UV filters—titanium dioxide, zinc oxide, and cerium phosphate—using zeta potential and particle size analysis. Zeta measurement identified titanium dioxide as the UV particle with the least tendency to agglomerate, and particle size analysis revealed its smallest and most uniform distribution, confirming it as the optimal raw material.
To improve stability, we coated titanium dioxide with silica to minimize photocatalytic activity. Acid titration confirmed the coating, revealing an isoelectric point consistent with silica, which indicated successful surface modification. Following the modification, particle size measurements showed a slight increase attributable to the coating layer.
Using the Turbiscan, we compared stability between formulations with uncoated and silica-coated titanium dioxide at 25 °C and 54 °C. The silica-coated version showed lower Turbiscan Stability Index (TSI) values, indicating improved stability and reduced agglomeration. This workflow ensured a stable formulation capable of maintaining SPF performance and resisting environmental conditions.
What sets Microtrac’s technologies apart for formulation research?
Our technologies are non-invasive, fast, and capable of analyzing native samples without dilution. They combine advanced measurements of particle size, zeta potential, and stability to deliver actionable insights, enabling researchers to optimize formulations efficiently and predict product shelf-life with confidence
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About Serife Korkmaz
Serife Korkmaz is the Turbiscan Application Engineer specializing in particle characterization technologies, currently based in Toulouse, Occitanie, France. With extensive experience at Microtrac MRB, she excels in technical support, pre- and post-sales services, and bridging R&D with marketing efforts. Her expertise includes method development, market analysis, and application discovery.
She has a strong foundation in chemistry, holding an engineering degree in chemical formulation from the École Nationale Supérieure de Chimie de Lille (ENSCL) and a master's degree in polymer systems engineering from the University of Lille. Her professional journey includes roles in research and development at Bollig & Kemper France and Sika, where she focused on industrial coatings and adhesive formulations, as well as quality control experience at Çağlayan Kimya in Turkey.
This information has been sourced, reviewed and adapted from materials provided by Microtrac.
For more information on this source, please visit Microtrac.
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