VINYL CHLORIDE different area with GC-FID

I am trying to create method for vinly chloride in MeOH (GC-FID) and i did it but disturbing is that with every next inj peak area of VC is lower (on the same method's parameters).
First inj area is about 200, next 180, next 150... FOR THE SAME CONCENTRATION. Thinking

Method is short - it has only about 4,5 min. I know that VC is volatile but maybe is also another reason? Have anybody any solution for that problem? :)

Parents Reply
  • okey im back!

    I inject VC with parameters as you said and split 1:5 and the results are amazing! Every of 3 inj are same - area: 1)37,89; 2)38,24; 3)38,26 :) thank you so much.. could you please explain me how did you come up with that? This flow 30:300:30 - i understand, sample is longer in colum but what about inlet - how temperature can change that?

    Im really thankful! 

    I also see something that RT of peak is with every ijnection earlier, I mean:

    1st: 2,186 min

    2nd: 2,180min

    3rd: 2,174min .. have you got any idea? 

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