Open Capillary Method

The open capillary melting point is also known as open tube- or sliding melting point (SMP). It's the temperature at which the sample rises in the tube under hydrostatic pressure. It can be used for atmospheric substances that cannot be ground and that melt at a temperature below the melting point of water (such as lipids, wax, paraffin, vaselines, resins). Use a glass capillary open at both ends with an approximate length of 80 mm, outer diameter of 1.4-1.5 mm and inner diameter of 1.0-1.2 mm. Melting point is the temperature, at which the substance in the capillary begins to rise. In those cases when the substance does not rise, the melting point is the temperature at which the substance becomes clear.