Question

1. In this experiment we injected the sample to be analyzed by Gas Chromatograph equipped with an FID (Flame Ionization Detector). The detector ionizes the sample as it reaches it, and the peak is proportional to the number of ions with a live flame. A chemist performed a distillation of methanol and water and wanted to analyze the results using the same GC instrument with FID. Could he use a similar procedure to analyze the results of his experiment? Explain why yes or no?

2. Ethylbenzene and o-xylene can be separated and analyzed using GC without injecting anequimolar standard to a high accuracy. Explain why that is the case for these two compounds while we had to inject an equimolar solution for our experiment.

3. The separation of two liquids on the GC is very similar to the distillation process.Compare the two methods describing the process while pointing out to the similarities and differences between the two methods.

Answer 1

1. NO. Because the MeOH and the water does not ionizes easily (These are not Ionic compounds).

2.The gaseous compounds being analyzed interact with the walls of the column, which is coated with a stationary phase. This causes each compound to eluteat a different time, known as the retention time of the compound. The comparison of retention times is what gives GC its analytical usefulness.

3. Both processes separate the components of a mixture primarily based on boiling point (or vapor pressure) differences. However, Distillation is typically used to separate components of a mixture on a large scale, whereas GC can be used on a much smaller scale (i.e. microscale).

Gas chromatography is also sometimes known as vapor-phase chromatography (VPC), or gas–liquid partition chromatography (GLPC). These alternative names, as well as their respective abbreviations, are frequently used in scientific literature. GLPC is the most correct terminology.