Simple Distillation and Gas Chromatography

Simple Distillation and Gas Chromatograpy In this experiment we demonstrated the methods for purification of volatile compounds and that gas chromatography may be used to quantitatively determine the relative proportions of volatile compounds in each sample. To do this, we performed a simple distillation of a new mixture of Hexane-Heptane. We then collected three different fractions from the distillation, recorded the temperatures each time. Then using chromatograms, we compared the three fractions we obtained and determined the percentages of Hexane-Heptane for each fraction collected.
In a gas chromatogram, the peak areas are considered to be directly proportional to the amound of sample passing the detector in the gas chromatogram. The table below shows the areas for each peak in each of our printed Chromatograms and the temperature at which we collected each fraction.
Fraction # Peak # Area of Peak Temperature at which Fraction was collected
1 1 2353548.74 29.9-37.7 degrees C
2 1 No Peak Recorded 38.6-39.9 degrees C
3 1 153621.26 39.9-49.2 degrees C 2 1431547.82 39.9-49.2 degrees C
Left Over 1 2896057.41 Room Temperature
These peaks were taken with a Hexane-Heptane Mixture
We can read several things from these results. First is that the largest area of a peak that we recorded was the material that was left over from our distillation. This tells us that there was still a lot of mixture that was not distilled. Most likely, because Heptane has a higher boiling point than Hexane, most of the solution still left over that was recorded in the GC was Heptane.
Another thing that sticks out is that there was no peak recorded in our second fraction. This could mean several different things. Because no peak was recorded, it leads us to believe that a bad fraction was taken. Because this was the second fraction taken, there should be two