TO-15 Analysis using the Marks UNITY2 and CIA Advantage
Posted: Mon Jan 20, 2014 5:59 pm
Has anyone ran into trouble with the 1mL internal standard loop?
I have been trying to play with the split to get good recovery of my IS but when I do I overload the GC/MS. The best I have come up with is running a 10:1 split to get my IS around 500k counts. 5ppb runs around 5M counts with my 200ppb around 20M counts. I did go as far as 500ppb but the calibration cure started becoming quadratic.
I have talked with Marks and they can not swap out the IS loop for a larger loop (10mL would be nice)
The linear range is excellent at 80:1 split (5ppb to 1ppm) with good RSD and R squared values for most compounds but my IS is almost nonexistent.
Any suggestions?
Thanks,
Jones
Other info you might ask for:
Agilent 7890GC, 240 ion trap MS
Scotts Gas 1ppm IS.
Rxi-624 30m, .25mmID
I have been trying to play with the split to get good recovery of my IS but when I do I overload the GC/MS. The best I have come up with is running a 10:1 split to get my IS around 500k counts. 5ppb runs around 5M counts with my 200ppb around 20M counts. I did go as far as 500ppb but the calibration cure started becoming quadratic.
I have talked with Marks and they can not swap out the IS loop for a larger loop (10mL would be nice)
The linear range is excellent at 80:1 split (5ppb to 1ppm) with good RSD and R squared values for most compounds but my IS is almost nonexistent.
Any suggestions?
Thanks,
Jones
Other info you might ask for:
Agilent 7890GC, 240 ion trap MS
Scotts Gas 1ppm IS.
Rxi-624 30m, .25mmID
