BFB on column calculation

[nmcm17]

How do you calculate 25 ng on column using 25mL purge & trap and 50:1 split?? Thanks for your help.

[James_Ball]

How do you calculate 25 ng on column using 25mL purge & trap and 50:1 split?? Thanks for your help.

25ng on column at 50:1 requires 25ng*50=1250ng to hit the injection port. 1250ng/25ml=25ng/ml in your sample which is equivalent to 25ppb.

So if you are using 25ml purge volume then a 25ppb concentration should give you 25ng on column.

I think my math is correct on that, but someone else should probably double check it.

[nmcm17]

Thanks for your help James_Ball!

[Bigbear]

What matters is if the BFB tune passes. The 25 ng value is a maximum ( EPA 524.2). I purge 25 ml sample that has BFB in it at 5ppb ( 25 ng). I split 150:1 so I think I get ~0.17 ng on column. My BFB passes.