GAS Chromatography???

[superstar1]

Hi, ive got a SAC on chromatography (mainly GC) and i wanted to know what type of questions might actually apperar on the Test.
Does anyone have any Chromatography questions? thanks

[Aurelian]

Hmm... let's see

Stuff like where you're given 2 substances, and asked to identify which will have the longer/shorter retention time are pretty common.

As well as that, questions regarding what factors have what effects on Rf values for TLC/Paper or retention times for chromatography will also probably appear.

Other than that, the only "calculation based" question I could think of would be regarding the calculation of Rf values, so no how to do them...

That's all I can think of right now, hope that's helped!

[Greatness]

You may get 3 substances and have to compare those to a sample. The  questoin may ask: Which of the following compouds are in the substance? here you would look at the rf values or just look at the chromatogram to see which substances are there. I remember doin one like this in the Heinemann textbook.

[superstar1]

thanks alot both of you, yeh i know how to do the calculations part, but its the explanation where you have to compare with other techniques that i find confusing. any help??

[Greatness]

Well you should know what kind of substances different techniques are used for, how they are different i.e. what do they do? how do they affect the moleucles/components, which ones are cheaper, faster etc
Since its only about chromatography, learn the theory about all the different chrom. techs and also understand and know them.