Cryoscope enables freezing point determination of up to 40 samples per hour
Credit: FunkeGerber
The measurement of water additives plays an important role in the quality control of milk. Freezing point determination (cryoscopy) is used to determine the extraneous water content of milk. The devices used for this should work quickly and precisely without being affected by external influences such as high ambient temperatures or fluctuations in air pressure. A manufacturer in the field of cryoscopy, Funke-Gerber, has made significant improvements to its CryoStar automatic. The device now works quickly and reliably even at 40 °C room temperature. The newly added pressure sensor warns promptly of pressure fluctuations so that there are no undesirable deviations in the measurement process. All settings and measurement curves can be conveniently made and viewed via the touch display.
In modern milk production, quality assurance is the top priority. “Adulteration, for example by diluting milk with water, can not only shake consumer confidence, but also have legal and financial consequences,” says Konrad Schäfer of Funke-Dr. N. Gerber Labortechnik.
Reliable testing of milk composition is therefore essential for farmers, dairies and companies in the food industry. A central role is played by freezing point determination, which is a proven method for quickly and reliably detecting possible adulterations caused by water or defective milk processing equipment. The challenge here is that the devices used for this must not only deliver fast and reproducible results but also withstand external temperature fluctuations and room temperatures of well over 30 °C without deviations in the results due to insufficient sample cooling, for example.
For the first time, the device now has an integrated pressure sensor. This triggers a warning signal if the air pressure fluctuates significantly or reaches a value that has an undesirable influence on the freezing point determination.
A rotary magazine on the machine offers space for 12 samples. These are measured automatically in sequence. Depending on the setting, the first measurement result is available after 90 seconds, resulting in a maximum sample throughput of 40 samples per hour. The cooling unit has also been redesigned and the newly developed control electronics reduce the waste heat generated. Together with improved heat dissipation, measurements can also be carried out at room temperatures of up to 40 °C.
The device exhibits strict linearity in the defined measuring range. “We guarantee continuous linearity in the measuring range from -1.5°C to 0°C, with a linearity error of less than 0.001°C. This eliminates the need for additional calibration, even for measurements outside the calibration range,” explains Schäfer. This is advantageous if, for example, the measurement is used to check that milk is lactose-free.
Automatic calibration saves time and minimises sources of error by saving all settings and calibration values. All settings, menu items and measurement curves can be made and viewed via the touch display. “This means that the plateau search (according to standard DIN / ISO / IDF 5764) can be checked and tracked in real time. We have patented this display method,” says Schäfer. In order to export the results, CryoStar can be connected to printers and PCs in accordance with laboratory standards due to suitable connection options.
All parameters can be freely programmed so that the device can be adjusted to all current and future national and international standards. The CryoStar also supports a growing number of languages. In addition to the currently installed German and English options, the device can easily be set to other languages through updates.