If you are very sure that each peak is related to an isomer and not a result of peak splitting due to wrong chromatographic conditions and

if you are sure that the isomer ratio is constant (origin does not change, no epimerization due to sample prep,...)

then you can work with the most convenient peak

Josephine

Can you provide conditions of your analysis and post here a chromatogram?

Regards

G

If you are sure that the peaks appearing in chromatogram can be assigned to the concerned simmers the you can quantify provided you separately inject pure simmers too under the same programmed conditions. Retention time for each of the isomer peak in the sample should match with that of standard isomer peak.

If peak retention time confirms to respective isomer, quantify as separate and individual peak against standard. If response for both isomer is same you can quantify against other isomer.

This is a sample chromatogram acquired using SIM mode for three ion channels 163, 181, and 165. I used temperature programming starting at 50 oC (for 1 minute), then increasing at 30 oC/ minute to 200 oC and then 4 oC/ minute to 300 oC. The injection temperature was 250 oC. I have tried varrying the chromatographic conditions but i consistently get two peaks. Should i quantify each peak separately or is it okay to use the most intense peak?