Semi-Micro Osmometer K-7400S instructions, V3700
Operation
17
To perform a measurement, the sample solution is cooled down first
with out stirring. Even pure water can be super-cooled down to about -5
through -8 ° C without freezing. The freezing is initiated by an automati-
cally start of the stirring wire at a set temperature. The temperature rea-
ches the freezing point, 0 ° C in case of pure water (Fig. 6).
Fig. 6:
Temperature-time-curve for pure water
The freezing point of a solution is below 0 ° C (Fig. 7). The freezing point
depression ΔT is a measure for the osmolality of a solution. It can be read
directly from the display given in mOsmol /kg.
Fig. 7:
Temperature-time-curve for a sample solution
During a measurement, the actual temperature is displayed. The device
detects the maximum temperature reached, stores it, and if crystallization
occurred satisfactory, displays the result.
