Chromatography

2. A noble gas commonly used as the mobile phase in gas chromatography (6)
5. Non-polar molecules will be attracted to a non-polar surface primarily by _________ forces (10)
7. The __________ of an analyte in a chromatogram is generally proportional to its concentration (4,4)
9. HPLC uses a fixed volume __________ in the injector valve to control sample volumes (6,4)
12. The _______ of a substance can be used as a first approximation to determine its retention time in GC (7,5)
13. In TLC, if we are using a hexane:ethyl acetate solvent mixture as the mobile phase, decreasing the ratio of hexane:ethyl acetate will make the mobile phase more ______ (8)
14. A TCD is a _______ detector because it responds to any substance that has a thermal conductivity that is different from the mobile phase (9)
15. The x-axis of any chromatogram (4)
16. _________ standards are often used in gas chromatography because it is difficult to reproducibly control injection amounts (8)
17. Thin layer chromatography on a silica plate with hexane:ethyl acetate as the solvent is an example of ________ liquid chromatography (6,5)
18. Hypothetical zone in a column where two phases of a substance establish equilibrium with each other (11,5)

1. A measurement of the amount of separation between two peaks with different retention times in a chromatogram (10)
3. 5 ______ is a common size for HPLC stationary phase particles (11)
4. Time elapsed between sample introduction and maximum signal of an analyte (9,4)
6. A C18 coating on a silica particle makes the surface of the silica _________ (8)
8. Property that is commonly used to detect molecules in HPLC (10)
10. The part of a chromatographic system that moves (6,5)
11. A ___________ column in GC has the stationary phase directly absorbed on the inner wall of the column (9)