【Daily Question】2018.7.7
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Fill-in-the-blank: The principle for selecting a stationary phase in gas-liquid chromatography is ( ). like dissolves like
Generally, the stationary phase is selected based on the properties of the components in the sample to be separated, following the principle of \"like dissolves like.\" ①To separate non-polar substances, a non-polar stationary phase is generally used. The components elute in order of increasing boiling point ； ②To separate polar substances, a polar stationary phase is generally used first. The components elute in order of increasing polarity ； ③To separate mixtures of polar and non-polar substances, a polar stationary phase is generally used; in this case, the non-polar substances elute first, while the polar substances (or those that are easily polarized) elute later.
There is no strict rule for selecting the stationary phase in gas-liquid chromatographs; generally, the stationary phase is chosen based on the sample. The separation characteristics of the stationary phase are the basis for selecting it, and this is generally done based on the principle of like dissolves like.