How to Analyze GC Results for Lab

A lesson in how to analyze gas chromatography (GC) lab results including peaks and percent composition of mixtures.

Get the guide and sample lab report here:

[hazeld]

Thank you so much! In just over 10 minutes, you taught me what a GCM was and how it worked as well as exactly what I needed to know to analyze the results which neither my teacher nor my textbook nor my TAs could do for me so thank you again

[SpencerFH]

when you describe the matching of peaks to boiling points, you put a dash in between y and z and their boiling points but not x. this makes it look like they are negative (-82 and -37) while x is positive.

[oandalevelchemistry]

Good video. A point to be noted: different compounds yield different peak area even if they have the same concentration; e.g. 100ppm of X, 100ppm of Y, 100ppm of Z will not yield the same peak area. Taking only the areas to calculate selectivity/composition could yield wrong results. The compounds need to be calibrated and their respective concentrations should be used to calculate composition and selectivity.

[skitlles]

This was so helpful! In the age of online learning this was the best thing that I came across all semester!

[rachelhughes]

Shouldn't the x and y be swapped over? The peak is high so I'd of thought x would be in the second highest peak? I thought it goes in order of boiling points to high and low peaks. If that makes sense

[brittnhuli]

great explanation! a little feedback... for the visual learners it would help to add a diagram of the standard gas chromatography setup, while youre explaining how the gas is passed through the coils. and put it next to the graph while youre explaining that the nonpolar parts are expelled first.

[mrphysh]

I am sure that you were a very good student. I bet you got an A in every class you ever took! Good job

[jemimamoses]

Thank you for this simple and clear explanation! This will help me a lot.

[Laura-hjkk]

really informative, helped me understand a lot more! thanks!

[clementinenamazzi]

Thank you very much it is informative, there are samples with over 60 compounds do i do the same to get the percentage of each?

[jackdawson]

How do we get the value of area of retention time 3.1 minutes i.e. 22375

[sophies]

isn't y=-82C the lowest boiling point? idk if thats a typo because you just say y=82 when u talk but wrote something else.

[judeonwudili]

To use this 'simplistic' method, you must make it clear that you have assumed or confirmed that the 3 components have similar (even the same) response factors in the particular detector being used.

[gbbanaag]

Thanks really helpful, but if we have 2 compounds that have similar boiling point 1 cis and 1 trans which one has the lower retention time? Appreciate your feedback. Thanks

[sankarasubramanian]

Thanks a lot. Simple and clear explanation.

[stephennguyen]

Can we able to calculate of RF value when we have GC report which allow us to know retention time and area which is in μV-s? Thank you very much.

[LyricGraham-ow]

How did you get the precise areas? Is there a table in MestreNova that shows the peak width and exact intensity that can then be used to calculate the area? Thanks

[KacyKhietNguyen]

what if there is 3 possible products but the GC data only show 2 peaks what does that mean, how do I know which one is which one and what is present of not

[khyrullahkhan]

thank you dear its so simple and can clear all the aspects..

[budia]

Thanks You very much, It is very good lesson for the GC understanding, but I still not clear for the area to be Calculated