Separation of analytes
Separation of analytes - contextAnalyte mixtures and separation - 1Analyte mixtures and separation - 2Analyte mixtures and separation - 3Introduction to chromatographyChromatographic columnsPrinciple setup of a chromatographic unitExample of separationChromatographic system - 1Chromatographic system - 2Standard gas chromatograph(Old) liquid chromatography unit(New) liquid chromatography unitHPLC columnsComparison GC and HPLC
SelftestProblems
1) GC-columns Answer 2) Which peak corresponds to 1,2,4-TCB? Answer 3) Peak area 100 times larger Answer 4) Unlabeled GC columns Help Answer 5) Which animation is correct? Answer 6) Concept map Hint
End of chapter4) Unlabeled GC columns
Problem:
You are working in a laboratory. In a drawer, you find 2 old GC columns that have no labels. In order to find out the characteristics of the stationary phase, you inject standards of the following substances on both columns: o-xylene, benzaldehyde, and phenol. At 100°C (isotherm), you obtain the following retention times:
| Substanz | Column 1 Retention time (sec) |
Column 2 Retention time (sec) |
| o-Xylene | 145 | 100 |
| Benzaldehyde | 170 | 320 |
| Phenol | 97 | 2900 |
4a) Based on these findings, what can you say about the properties of the columns?
4b) You need to separate benzene from the three substances o-xylene, benzaldehyde, and phenol. Based on the above findings, would you expect that it is possible with one of the above columns? If yes, which one?
4c) You need to separate anisole from the three substances o-xylene, benzaldehyde, and phenol. Based on the above findings, would you expect that it is possible with one of the above columns? If yes, which one?
Help:
4a) You need to know the chemical structure of the given compounds. If you do not know them, look them up: www.chembiofinder.cambridgesoft.com.
4b) Think about the interactions that these compounds can undergo (see Chapters 3 and/or 4 in the script).
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