Question

9 VII. Gas Chromatography 1. The organic mixture to be separated on the GC is injected into the GC as a (gas, liquid, or solid). 2. The typical volume of mixture injected into a GC is 1-10 (microliters, milliliters, or deciliters). 3. Immediately upon entering the injection port the mixture is_ _(solidified, condensed, or vaporized). (heated, cooled, maintained at room 4. The event described in #3 occurs because the injection port is temperature). 5. An inert gas, referred to as the gas, sweeps the mixture through the column 6. The inert gas (described in #5) constitutes the_ phase in GC. 7. There are two different types of columns used in GC. One is a packed column (typically 5-10 feet long with a 1/8 inch diameter) and the other is a _ _column (typically 30—100 meters long with a 0.1 mm pore). 8. As the mixture travels through the column the compounds that make up the mixture are said to be (positioned, partitioned, or placed) between the inert gas and the nonvolatile liquid. 9. Generally compounds with _ (low or high) boiling points travel through the column the fastest. 10. Instead of an Rr value, the time of a component is reported. This quantity is read off the x-axis. 11. Another factor affecting the quality of the separation is the rate of the inert gas. 12. The oven___can also affect the quality of the separation. For example, if it is too high all the components may exit the column at the same time. of the nonvolatile liquid. The 13. The of the compounds in the mixture should also match the phrase "like dissolves like" reflects this guideline. 14. The area a under peak corresponds to the of that compound in your mixture,

Answer 1

Answer 1. Gas. (The organic mixture forms the mobile phase which is injected into a stationary phase.)

Answer 2. Microlitres. (the sample volume is low in GC for optimum column efficiency)

Answer 3. Vaporized. (When the sample is injected through the septum, the mobile phase enters the column present in the chamber and vapourizes  to form a mixture of carrier gas, vapourised solvent and vapourised solutes.)

Answer 4. Heated ( The temperature kept depends upon the boilling point of the sample. so the temperature is slightly above the average boiling point of the sample. The column temperature can be programmed on that basis.)