osmometer การใช้

• Thermal hysteresis is easily measured in the lab with a nanolitre osmometer.
• Another issue for membrane osmometer is the limited membrane types.
• It often takes 3 or more hours after the solute is added for the static osmometer to reach equilibrium.
• Osmolarity can be measured using an osmometer which measures colligative properties, such as Freezing-point depression, Vapor pressure, or Boiling-point elevation.
• The Clifton nanolitre osmometer is especially well suited for determining the antifreeze activity or thermal hysteresis of a solution, which is a difference in the melting and freezing point of a solution.
• It is necessary to calibrate a vapor phase osmometer and it is important to note that "'K "'is found for a particular solvent, operational temperature, and type of commercial apparatus.
• A typical vapor phase osmometer consists of : ( 1 ) two thermistors, one with a polymer-solvent solution droplet adhered to it and another with a pure solvent droplet adhered to it; ( 2 ) a thermostatted chamber with an interior saturated with solvent vapor; ( 3 ) a liquid solvent vessel in the chamber; and ( 4 ) an electric circuit to measure the bridge output imbalance difference between the two thermistors.
• However, looking at two totally different formulas for the expected serum osmolality [ https : / / www . khanacademy . org / test-prep / mcat / physical-sciences-practice / physical-sciences-practice-tut / e /-using-a-freezing-point-depression-osmometer-to-measure-serum-osmolality, what they have in common is that the concentrations of sodium, glucose, urea and in one potassium are used to come up with a figure that, in the second, is about 280-300 mOsm, ( this says 275 to 290-if I were anywhere near serious I'd need better sources than any of these, but this is strictly back of the envelope / order of magnitude ) where apparently 1 Osm = 1.86 K freezing point reduction ( that number being the cryoscopic constant ).