Chromatography Forum

I have a question regarding multiple headspace extractions.

After plotting the natural log of peak areas, you obtain the slope of the linear fit from this.

Is there a general lower limit for an acceptable slope? A colleague mentioned to try to get the slope above 0.4. I have seen some technical papers with slopes as low as 0.05! I am looking at high boilers in elastomers, and in order to increase the slope, the temperature has to be increased too high and lots of degradation peaks are observed.

Obviously the steeper the slope the better, but what really matters is the uncertainty of the slope compared to its steepness.

Flat slopes mean that the quantity of what you are measuring is not being depleted enough by the headspace sampling on each run. If you reduce the amount of sample in the vial you should see steeper slopes.

Peter