1、 What is osmotic pressure?

Separated by a semi permeable membrane, one side is water as a solvent, and the other side is a solution. Water permeates through the semi permeable membrane towards one side of the solution. The pressure applied on the solution side to prevent the movement of water is called osmotic pressure. The reason why the movement of water stops is that the pressure is equal to the chemical potential energy of the water passing through the membrane. The osmotic pressure П of a solution with a molecular weight concentration of Cs is approximately П=CsRT (R: gas constant, T: temperature). If using volumetric molar concentration, larger measured values than theoretical values can be obtained. Plant cells with well-developed liquid cells have a constant relationship of П V with cell volume V; But in cells with abundant cytoplasm such as animals, the above equation also holds when subtracting the cell volume of the non water phase that is impermeable from V. Maintain osmotic pressure balance in plant cells, cytoplasm, and cytoplasm. The osmotic pressure of cell fluid limits the water content of the cytoplasm and affects its physical and chemical properties such as viscosity. In addition, osmotic pressure can also generate swelling pressure to regulate cell growth and swelling movement. Cells have the function of regulating osmotic pressure, which is called osmoregulation. Just like animal body fluids, the osmotic pressure of the internal environment that impregnates tissues also has a significant physiological impact. Osmotic pressure can be measured using air pressureFreezing point osmometerExpressed in terms of degree of decrease (△) or osmolarity.

2、 How to choose an osmotic pressure gauge?

　　1.Freezing point osmometerThe measurement was carried out using the principle of low pressure at freezing point, and the test results showed good repeatability and linearity. Freezing point low pressure technology is currently the standard for the production of osmometers in the vast majority of laboratories worldwide.

Dew point osmometer applies the principle of boiling point rise and water vapor pressure technology to measure the osmotic pressure of a sample by heating and evaporating a solutionFreezing point osmometerCompared to freezing point, the test results are not as accurate and have poor repeatability.

　　2.Freezing point osmometerThe sample testing probe is easy to wipe and clean, requires minimal maintenance, and has a long service life. Under normal usage, it can be used for ten years or longer.

Dew point osmometer is a measurement instrument that uses a thermocouple to condense the vapor generated by the evaporation of a solution sample. After testing 100 samples, the thermocouple needs to be cleaned. The maintenance workload of the instrument is large and the maintenance cost is high. Due to the fact that thermocouples are inside the instrument, they need to be disassembled for cleaning, and thermocouples are prone to breakage and require frequent replacement.

　　3.Freezing point osmometerAdopting semiconductor refrigeration, utilizing the physical properties of semiconductors themselves, does not require daily maintenance, and has a long lifespan.

Dew point osmotic pressure meter is heated by electric heating wire, with a service life and accuracy lower thanFreezing point osmometer.

　　4.Freezing point osmometerThe design is mainly applied in clinical research and detection of vital fluids such as mammalian body fluids, blood, urine, etc. It has been widely studied by clinical researchers and drug researchers.

Dew point osmometers are mainly used for ecological research and are suitable for plants and invertebrates.

Dewpoint osmometers cannot be used to detect samples of volatile solutions such as ethanol and ether, especially those that are easily decomposed by heatFreezing point osmometerOkay.

　　5.Freezing point osmometerEasy to operate, no need for daily maintenance, long calibration cycle.

Dew point osmometers need to be calibrated regularly.