Chromatography Forum

Hi all,

I would like to know how can I develop a method that is useful for my analysis. Actually, had just graduated from college and is very new and inexperience with GC. Though did use them in sch before, but was all afterall more observations than hands-on.

Anyway, I'm using Shimadzu 2010, had tried to use the default values listed in the manual for my analysis. But no peaks was observed and mostly encountered errors messages. I don't have a senior that I can check with and thus would like to check with all of you.

Suppose you are told to check for a compound in a water sample. Just one component. How would one go abt testing its concentration and retention time, etc when using a GC? What do we need to consider before we start the test?

Thx very much
belle

Dear belle,

First of all, tell us what is the compound (or chemical type of compound) that you're analysing. What do your water samples contain, except of the target compound?
Do you have headspace sampler coupled with the GC?
With which detector(s) is your GC equipped?
What types of columns do you have at disposal?
Which carrier gas are you using?

hi zokitano,

First of all, tell us what is the compound (or chemical type of compound) that you're analysing. What do your water samples contain, except of the target compound? Right now, I'm at the initial stage, i.e. am injecting a known standard of diethelylene glycol. But I'm still unable to get any peak. Wonder if it's due to the method that I used...Also interested in glycerine, dimethylacetamide, Polyethlylene glycol, had gotten some info abt them through another post of mine...)
Do you have headspace sampler coupled with the GC? Not too sure of an headspace sampler, is it the same as an auto-injector? If it is, yes, it's coupled.
With which detector(s) is your GC equipped? FID
What types of columns do you have at disposal? 50m Carboxwax
Which carrier gas are you using? He

Is the method that I used wrong that caused my compound unable to elute? Or there may be other factors as well? One method employed maybe useful for one compound but not for others. So how am I able to establish a method that allows me to have good separation of different compounds?

Do let me know if there's any infomation that is needed. Greatly appreciated all help.

thx
belle

well, I think to get a catalog is a good starting point. We have Restek, Agilent or Sulpeco. You can find a lot of applications there, with columns and chromatographic settings for a compound or family of them ( just search in the GC applications of the catalog, for example pesticides, phenols, glicols, vocs, xilenes, hidrocarbons,etc). these books contain a lot of useful information too.