How to Analyze GC Results for Lab

[@hazeld8016]

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.

[@parfumsensa1]

hahhah

[@oandalevelchemistry8095]

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.

[@Alfalfaello]

I was actually looking for this comment. Thank you! It was essential to clarify it

[@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

[@rachelhughes2837]

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

[@skitlles1923]

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

[@sophies8107]

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.

[@Miyakimiki]

He wrote the "-" as a reference to connected it to y. It's confusing because he didn't do it for "x". But it's meant just to show y - 82 to show that y is 82 (it is not -82).

[@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.

[@ChemComplete]

Thank you for the constructive feedback. I will consider in in future work.

[@clementinenamazzi7852]

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?

[@judeonwudili9619]

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.

[@ChemComplete]

This is true and does need to be accounted for in more complex lab work and mixtures. This video is aimed at students first experiencing GC labs in general or organic chemistry. It would not be appropriate to teach response factors until an upper level course such as instrumental chemistry or an advanced spectroscopy course.

[@AliAsghar-ue4lm]

Percentage composition is by mole % or mass %

[@cdietrich3252]

(SUMMARY of text below): GC gives mole %. readings (percentage composition = mole %) (MORE DETAILS) I'm wondering this as well! I am 99% sure that percent composition for GC is by mole %. My thinking is that percent composition assumes "amount," and "amount" is always by moles. He also states in the video that "the GC does not know what chemicals you have," so mole% makes the most sense as the GC does not know anything about the masses of each component, which it would require in order to find mass%.

[@gbbanaag3954]

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

[@ChemComplete]

In GC compounds are separated by relative boiling points. Look for the lowest boiling point and it should be your first peak.

[@jackdawson7385]

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

[@StephanieNartey-s9z]

Are you assuming that the chromatograph , gives the area under each peak

[@Laura-hj2kk]

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

[@ChemComplete]

Glad to hear it!

[@crazygokerff2517]

@@ChemComplete Hi the percentage you calculated is the sum of peak Hight to assume the concentrations of product

[@LyricGraham-o8w]

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

[@galaxy6251]

bro stretches this out wayyyyy longer than it needed to be

[@khyrullahkhan6242]

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

[@stephennguyen9476]

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.

[@jemimamoses7212]

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

[@budia3070]

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

[@cheyma7945]

You're a life saver!!

[@tubetigeerr]

does the machine automatically calculate the area? thanks

[@ChemComplete]

Often times it may, especially with more modern instruments, but not a guarantee.

[@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

[@anamikaG28]

May I know how to calculate the area of the peak, as in real graph, the peaks are not very sharp as triangle where we could apply triangle area formula. Kindly let me know from where will I get the area of the peaks.

[@sankarasubramanian5053]

Thanks a lot. Simple and clear explanation.

[@Beautifullife7189]

Sir how to calculate the area of any retention time

[@andrewjustin256]

What do those invariable peaks mean, some are long and some are short?

[@epalanisamiepalanisami6863]

Can we use Methanol solvent for edbileoil fame preparation?

[@nhatle6129]

how does z have lowest boiling point

[@marianafaria4233]

I think he meant 82°C instead of -82°C

[@mome123]

Really good video man! I was just wondering is it possible to use this method with a unkown sample withouth having ms or lc. And do you need to have the boiling point for all the molecules in you sample you testing before using this method ?

[@aneesabdullah3418]

The lowest boiling point (-82C) took the longest retention time, how ?

[@NamrataGawai28]

If mixture of methanol, acetone and MDC mixture which peak elute first . Elaborate your answer.

[@marcochimio]

I am presuming that the Percent composition is by mass, and not by volume or mole fraction. Is this correct?

[@NanaAdjeiwaa-ei6om]

Please can oxygen be used instead of zero air?

[@NamesIWantAreInvalid]

how would we adjust the ratio for the bias of a detector?

[@JonWu0716]

So helpful, thank you so much!

[@ForensicNA]

Thank you for making this video. it was clearly explained.

[@terenica]

how does this change if it is a relative retention time?

[@kienphamtrung5173]

how did you do it can you share with me , thank you

[@madhurpandey5000]

Please find out the area of pics

[@ireneaa5890]

thank you for this video! very excellent. Can you make a video of how to analyze essential oil using GCMs

[@mona199696]

Gerate Video , but i`m a bit confused do you mean y= 82 °c Or Why is it last to avaporate ?

[@mona199696]

Instate of minus 82*

[@kiranshahzadi2465]

how do you calculate values like 22.375

[@dhifarhasan6948]

thanks a lot, that's helped me so much

[@carmelaeugenio1746]

where did you get the area of retention? what is the formula?

[@ChemComplete]

Area is provided by the GC instrument. This is a random example teaching you how to utilize your data.

[@clip012]

How about Normalized Peak Area? Normalized against biggest peak and get corrected area?

[@inemesitakpan226]

what's the unit of the area

[@ChemComplete]

This can depend on the GC being used, but generally it is the area of the x and y axis units. So most GC will have minutes (retention time) along x and a volts (detector signal) on the y axis. So a common unit might be volts-minute.

[@aven2913]

Is that template ACS format?

[@humakhan7694]

How to calculate area then?

[@Poolshockguy]

GC shows 54 in area but under amount where it shows PPB it says -12,000. What does this mean

[@erzas556]

but how to calculate the concentration using the area and height?

[@ranarajeshwari9953]

Did u find it?? If u know..plz ask me..I have same problem

[@sunithas5782]

What would happen if retention times of compounds if the column temperature were raised?

[@MrsLacqueredClaws]

Hi, not the OP here, but doing GC lab work is my job, and generally speaking, if you expect a certain Rtime and your results show an Rtime higher than control (or reference), then you are looking at a similar, but ultimately different compound. RE: THC vs synthetic cannabinol

[@tulip811]

Hey can someone help. How can I get the quantity (in grams) from the area in % ?

[@olaleyeolutunde]

Nice and well explained

[@ezekasarachifelix4471]

Hi, can you make a video on waste engine oil analysis by GC?????

[@crosshiiro7970]

great video! Very informative, thank you very much

[@ChemComplete]

Glad it was helpful!

[@shyamlokhande3466]

How can we calculate the %yield of our product in reaction mixture using GC-MS, With or without taking any internal or external standard. Can anyone help??

[@Fummy007]

4:09 I thought it was minus 82 and got confused

[@ClutchDaddy91]

I know they say there are no dumb questions, but.. How is the area calculated for the compounds?

[@caseypickens8592]

You first draw a baseline (you would not use the x-axis line).Then you would measure from the top of the peak to the baseline to get the height and then to get the width, you would go to the halfway point on the height and then measure the width from there. So, the equation would be A= H x W(1/2) if that makes sense.

[@vithenych9605]

This does not seem right to me. Your calculation assumes the same detector response to all compounds. However this is not true. 50/50 % mixture does not generally make 50/50 % response. I would say you need to know the response factors to make the calculation.

[@xharuu]

how’d i get from my 8th grade chem class to this

[@jaykumarbhatt8841]

Thnks sir 🙏 Very good sir👍 Sir what is the effect of column I.D and film thickness ????

[@sabertooth_almas]

Very helpful, thanks!

[@Priyanka-tt8cg]

precise and informative

[@maximehendrickx6212]

Great video!

[@rachelhughes2837]

how did u calculate the 22,375 ?

[@akhileshchaurasiya9408]

Area of triangle formula put down in the peak portion

[@gollaprathima1134]

Thank you so much

[@ειμαιοκωστας]

but the area gives the mass or the mole percentage?

[@AliAsghar-ue4lm]

Have you got this answer ? Plz share

[@Beautifullife7189]

Thank you so much it is very informative videos

[@HadyAkAHady]

amazing job thanks

[@CienciaPelada]

Thank you!!

[@iraqi3612]

thank you so so much sir

[@ChemComplete]

Most welcome

[@kubra7996]

thank youuuuu for this video

[@vanderburg.M]

Excellent! cheers mate!

[@indrajeetw.5365]

Thank you.. Please make a video on, how to calculate selectivity and conversion by using GC...

[@saka_inrmy6293]

Thank u so much for this

[@bariumselenided5152]

Dude, I _knew_ this instrument had to be set up to give you the integral. Idk why but our professor has us doing this some weird way where we estimate the integral by printing it out and physically measuring height and width to get a rectangular approximation. Why? Why couldn't I just be given data if the instruments give you data? And if we're going old school, why not cut out the peaks and weigh them? At least that method is cool.

[@camid7403]

this helped so much!!

[@Aleu931]

Thank you

[@praveenmishra7863]

nice explanation.....

[@manashjyotibaruah6758]

This is helpful.

[@georgesunnyvarkey3425]

Thanks bro ❤️

[@franknjmt1]

Awesome!

[@Manifestinglove77]

Best video

[@georgesunnyvarkey3425]

Thankyu so much sir

[@AristotleFreeman]

the only one still sup this are the bot answers its hilarious.

[@rassimsimou1594]

G😊😊d

[@jibrilmunira86]

paying for this lab report was a waste of money. Nothing new in it.

[@rubaetm5353]

Dragon ball z is the best

[@humakhan7694]

That cracks me up... reading all the comments knowing might I will find my answer related to GC.. lol

[@anitaten3856]

thank you for such a helpful video!!!