GC Quantifiaication using Chematation

[ydna6969]

Hi .

I have not used Chemstation in many years on HPLC (and know it was a nightmare to quantify impurities) but never on GC
How do you go about calculating results using an internal std ratio?
Also the version of Chemstation is B.03.01 SR1,, not an issue ?
thanks

[Consumer Products Guy]

Chemstation is exactly the same for GC and for HPLC except for the one column for instrument setup on the first "Window". So same as the HPLC stuff was.

[ydna6969]

ok ,, eh ,, that doesn't really explain much though .

I can run a sequence but have not a clue how to quantify using internal std or peak area ratios.

Quantifying impurities on HPLC using chemstation ,, I get,, just !.. GC another can of worms !

[Consumer Products Guy]

I can run a sequence but have not a clue how to quantify using internal std or peak area ratios.

We use a Sequence Summary Report to get results in Percent. We use either ESTD% or ISTD% as appropriate.

[ydna6969]

ok ,,what value do you put in for internal std (%ISTD)

how do you quantify or create calibration curves ,,, for a number of peaks ?

[Consumer Products Guy]

ok ,,what value do you put in for internal std (%ISTD)

how do you quantify or create calibration curves ,,, for a number of peaks ?

I can't describe that in writing, would be too cumbersome. Even in person that would take me over an hour to teach someone. Go to Agilent web site and download PDF documents, or call 1-800-227-9770.

[KipDM]

i will be using IS to mean Internal Standard.

for single point calibration just enter the concentration for the IS and Calibrator drug, this should set the ratio to properly quantitate for the rest of the batch (this works best if you are using a dueterated analog of the drug as your IS).

you will need to set this for each individual drug (or peak).

i cannot remember the specific options from the menu you have to go through to get to these settings because i have not had to use them for a while and don't use this software at all with my current employer.

if you are using a multi-point curve to establish linearity for each batch i am not sure how to set this up, as we used to use GCMS for only single point calibration where the linearity had previously been established by QA/QC.

hope some of that helped,
KDM