When must liquids be vaporized according to specific measurement protocols?

Vaporization of liquids is essential when utilizing a chromatograph because this technique relies on the separation of components in a gas phase. In chromatography, particularly gas chromatography, the sample must be in the vapor state to be effectively transported through the column where separation occurs. This vaporization allows for the components of the liquid sample to be analyzed based on their different interactions with the stationary and mobile phases.

The necessity for vaporization in this context is linked to the principle that chromatographs are designed to analyze gases. Liquid samples would not be compatible with the method without first being converted into a vapor form. This ensures accurate analysis and measurement of the constituents within the sample through their respective retention times and responses.

In contrast, density measurement does not require vaporization, as density can be measured directly in liquid form. Purification may involve vaporization in some processes, but it is not an inherent requirement like it is in chromatography. Temperature measurement typically involves liquids being measured in their liquid state and does not necessarily involve vaporization to determine temperature.