Examine dispersions at minus temperatures

A dispersion stability analysis system can now analyze dispersions such as coatings at sub-zero temperatures as low as -10 °C. The extended temperature range enables measurements under real environmental and storage conditions.

Many products consist of complex multi-component mixtures. Long-term homogeneity and durability of such mixtures is often a high priority in product development because segregation processes have a negative impact on product quality. Traditionally, such segregation processes are observed with the naked eye in a so-called "shelf life test". However, this procedure is very subjective and often several weeks of testing are required for each optimization round.

To solve this problem, the German laboratory instrument manufacturer DataPhysics Instruments offers the dispersion stability analysis system MultiScan MS 20 for automatic stability and aging analysis of liquid dispersions. The instrument was specially developed for characterizing suspensions and emulsions and enables time- and position-resolved analysis of segregation processes. With the MultiScan MS 20, such processes can be quantified much more accurately and evaluated in greater detail than with a conventional shelf-life test. The MultiScan MS 20 consists of a base unit to which up to six sample chambers can be connected.

Up to now, the MultiScan MS 20 allowed measurements at constant temperatures and individually definable temperature profiles between 4 °C and 80 °C. The MultiScan MS 20 is now able to measure the temperature of the sample chambers. Now the laboratory instrument manufacturer has succeeded in lowering the minimum temperature for measurements to -10 °C. In order to measure at sub-zero temperatures, the tower-shaped sample chambers of the MultiScan MS 20 are encased in an insulating sleeve. To prevent humidity from condensing on the samples, the sample chambers are flooded with dry inert gas during measurement. The sleeves can be ordered in the desired quantity when purchasing a new instrument. Existing instruments can be retrofitted inexpensively for measurements at low temperatures.

Temperature is one of the factors influencing segregation processes in dispersions. Therefore, when investigating new or optimized mixtures, it is essential to study them under real storage conditions. Dr. Sebastian Schaubach, Chief Innovation Officer at DataPhysics Instruments, says: "We are particularly pleased to be the first manufacturer in this field to succeed in performing measurements at sub-zero temperatures." Further development of the MultiScan MS 20 has made it possible to examine dispersions under real storage conditions, even for products that are stored under refrigeration. The European Medicines Agency, for example, requires in its 2007 guidelines on the "Declaration of Storage Conditions" that medicines be tested for stability and then provided with appropriate labels. Here, storage in the refrigerator is based on a temperature of around 5 °C, while storage in the freezer is based on a temperature below 0 °C.

The extended temperature range is interesting not only for the pharmaceutical industry, but also in the food sector. Here, products are often stored refrigerated during production, transport and at end customers. The typical temperature of a refrigerator is often specified as 4 °C or lower. These conditions can now be mapped with the MultiScan MS 20. Similarly, the MultiScan MS 20 can now be used for products that are used outdoors. These include lubricants as well as paints and agricultural products. "The experts in our in-house laboratory combine an in-depth understanding of our measurement methods with a broad knowledge of specific applications in many industries," explains Schaubach. He continues, "We are also pleased to accompany customers on new, exciting measurement tasks in sub-zero temperatures." (OM-05/23)