Simple question, the gas chromatography graph shows two curves to show the ratio of two products. Will the retention time for each product always be in the same order for the two products? I am asking because we pooled class data, and although the ratios are the relatively the same, the order of retention time was different. For instance:

 

Data 1: 1.04min 40% 1.06min 60%

Data 2: 1.04min 60% 1.06min 40%

 

Can anyone explain? Thanks.

Or both samples have 50% of A and 50% of B and there is a 10% error in the experimental method.

Agreed.

 

Retention times should remain constant when a sample is re-analysed under the same conditions (column type, column temperature, carrier gas velocity etc).

 

So it appears that the concentrations of your sample A and B are different between Data 1 and 2.