ChromaTOF calibration - How to get it to work ??

[Fee]

Hi,

I am currently fighting (that's pretty much it...) with ChromaTOF (GC-MS-SPME method for aromas) to build my calibration (over 40 compounds) and I can get it to work correctly for all compounds.

Actually, the software can't find all the analytes and it seems to have a problem with the fact that peak width is changing troughout the chromatogram (I have very large peaks and trace components). So, when I am using a wide peak width (such as 30 sec - which is the case for some peaks), ChromaTOF can't find smaller peak OR it finds them but reject them as being out of the selected peak width. On the contrary, if I use a small peak width, such as 1-2 s (recommended by our sale representant), ChromaTOF can find 10 peaks within the same actual peak.

Iam getting to the point that I'll use two calibration, one for the large peak and one for the smaller peak... Is there another solution ? I already used the function "Peak broaden troughout chromatogram" (in the Data Processing Method form) but it didn't give satisfying results.

Another question I have is : where to set up the retention time window ?

Thank you so much for your help - I am "trying to like" ChromaTOF, but, as a former Agilent/MS user, I have hard time...

Fée

[Don_Hilton]

First question: Which version of ChromaTOF are you using? You want to be using one of the later versions of ChromaTOF 3.xx or a ChromaTOF 4.xx version.

Your sales rep should be able to locate a applications flier that circulated several years ago -- it was carried the name: "Leco Retention Times and Chronicle." There was an article on setting up integration parameters. And, as far as I know, even though there have been multiple updates to ChromaTOF since then, the advice is still good - but with one change. The newer versions of software have an "automatic" option for selection of the number of data points to average while doign the peak find. If you have the option of taking "automatic," do so.

If that does not work for you, contact me directly. e-mail: dchilton at mylink dot net I will happily take a chroamtogram and see what I can do for you. (And yes, replace the words at and dot with the symbols - I am trying to avoid junk e-mail from sites that search the web for addresses.)

With regard to being frustrated with ChromaTOF - After many years of working on ChemStation, I was away from ChemStation for several years. I now have had reason to work with it agin. And, much to my surprise, I have discovered that I get lost there, even though it was an old friend. So, like playing the piano - it only takes practice.