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13810491101@163.com
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13810491101
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Beijing Yasenbuoke Scientific Instrument Co., Ltd
What is the working principle of the freezing point osmometer?
Date: 2025-10-25Read: 3
Freezing point osmometer is a precision instrument based on physical and chemical principles to measure the osmotic pressure of a solution. Its working principle and workflow are as follows:
1、 Core principle
The freezing point osmometer calculates the osmotic pressure by measuring the drop in the freezing point of a solution based on the Raoult freezing point theory. According to this theory, the freezing point drop of a solution (Δ T)f）Directly proportional to the solute molar concentration (m), the relationship is:
Among them, KfThe freezing point constant of the solvent (1.86 ° C · kg/mol for water). The instrument detects the freezing point drop of the sample through a high-precision temperature sensor, and directly outputs the osmotic pressure (mOsm/kg) or molar concentration through formula conversion.
2、 Workflow
1. Sample preparation: Inject the test solution into a dedicated sample pool, ensuring that there are no bubbles and the volume meets the requirements.
2. Rapid cooling: Using semiconductor refrigeration or dual refrigeration systems to lower the sample temperature below freezing point, forming a supercooled state.
3. Crystallization induction: The sample temperature is uniformly lowered by weak vibration, and then strong vibration is applied to trigger ice crystal formation, releasing latent heat to raise the temperature to freezing point.
4. Accurate measurement: Platinum resistance or thermocouple sensors record the freezing point temperature in real time, and the data is converted from analog to digital to calculate the osmotic pressure value by the processor.
3、 Technical features
1. High precision: measurement error ± 2mOsm, repeatability error<2.5mOsm, superior to dew point method.
2. Anti pollution design: using oscillation method to induce crystallization, avoiding metal probes from contacting the sample, and reducing the risk of cross contamination.
3. Intelligent operation: equipped with a touch screen interface, supporting automatic calibration, data storage, and electronic signature functions.
4. Long life maintenance: The semiconductor refrigeration system does not require daily maintenance, and the probe life can reach more than 10 years.
This instrument is widely used in the fields of pharmaceuticals, medicine, and biological research, especially suitable for osmotic pressure quality control of key solutions such as cell cryopreservation solutions and injection solutions.