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- Posts: 3
- Joined: Thu Aug 15, 2019 5:22 pm
I'm injecting (splitless) a 6 uL sample that contains 0.12 pg native and 0.6 pg -D9 in the 6 uL. The solvent is MSTFA. I'm using a pressure surge of 40 psi to compensate for the high injection volume. My inlet temp is 190. My split flow is set to 50 mL/min after 1.00 min. The septum purge is set to constant. The surge is set to 40 PSI for 0.9 minutes.
The oven ramp is 80, hold for 1 min, ramp 35/min to 295, hold for 0.5 min. The analyte elutes around 7.1 minutes (near 295 degrees).
I'm getting this little pre-peak shoulder when I am only using the pure standard that has been dried and brought up in 25 uL MSTFA, heated at 70 degrees for 20 minutes, transfer to the AS vial. Any suggestions on what these little peaks may be and how to get rid of them?
Anyone know what the rules are for setting the timing of the purge, split flow start time, how long to keep the column cooled at the start of the run?