peak tailing and capacity factor issues

[LAUGH880]

Hi Everyone/Anyone,

I'm new to GC validation/method devlopment and I have been tasked with validating a GC method, I'm currently having issues with peak tailing and capacity factor K'.

I am attempting to quantify the %Proplyene Glycol within a sample.

The specification within the validation for tailing factors is <2, I am currently getting 2.1 2.2. I'm looking for ideas of how to reduce this or justify an increase of the specification?

I'm having a similar issue with capacity factor, I am currently getting a K'=1 the specification states K'=>2.
So does anyone have any ideas of how to increase the K' value or any ideas around a justification?

My Instrument set up is:
GC = 6890N with a 7683 auto injector,
Column = CP-Wax 52 CB column (0.32mm, 25m, 0.4um)
Injection Vol = 1.0ul
Split Ratio = 50:1
Inlet Temp = 250
Detector Temp = 250
Temp Program = 130 - 230 @ 20oc/min
Flow Rate = 2ml/min

The proplyene glycol is extracted from the sample using IPA, an internal std of 1,3-butandiol is then added before analysis.

It seems everyone has delegated this job and it is now at my door step with no where else to go.

So any help would be much appreciated,

[DR]

Liner shape, stuffing, silanization routine?

[Peter Apps]

The tailing is very likely to be coming form active sites in the inlet liner or the column. Put in a new liner (cheap and easy) before trying a new column (or cutting 1 m off the inlet end of the existing one.

Peter