SPME Headspace Sample Size

[Sassenach24]

I am new to GC/MS, and I work in the Drinking Water-Water Production-Water Quality Laboratory for a county water municipality. I have read Standard Methods for the Examination of Water and Wastewater 22nd edition, Method No. 6040D for SPME, and in it, it gives details on how to prepare my standards, and my sample collection, and everything I've read so far talks about using a 45ml sample in a 60ml vial. However, I'm finding it extremely difficult-if not impossible-to find a 60ml vial with a magnetic screw cap with the PTFE/SIL Septa. Wheaton makes a 60ml screw cap vial, but the caps are packaged separately, and none from Wheaton are magnetic. Every search for SPME Headspace vials and caps yields me results for sample sizes that are 10ml in a 20ml vial. Does anyone on this forum use Standard Methods, Method No. 6040D?, and if so, do you make your standards like it says to in Standard Methods?, and do you use a 45ml sample size in a 60ml vial?, or do you use a smaller sample size, such as 10ml, and simply multiply your results by 4.5? Please help, offer advice, suggestions, etc....

[rb6banjo]

I am not familiar with this method but to keep the phase ratio (Vliq/Vgas) in the vial the same: 45 mL water in a 60 mL vial is the same as 15 mL of water in a 20 mL vial. The trouble with this is that in a 15 mL of water in a 20 mL vial doesn't give a lot of room for the fiber to hang in the gas phase without touching the water.

These folks used a phase ratio of 1 (10 mL water to 10 mL gas) in their application of 6040D:

http://www.lecomexico.com/sepscience/TR ... 21-386.pdf

This reference also points to a 1:1 phase ratio (10 mL liquid and 10 mL gas) in a 20 mL vial:

http://www.chromatographyonline.com/ana ... raphy-time

I don't have access to the 6040D method so I can't read it for myself.

[BMU_VMW]

Maybe I can help you but I can't share entire methodes on the web.
So please send me an email
bart DOT mulkens AT dewatergroep DOT be