Split flow

[deng74]

Can someone explain to me the purpose of the split flow and what it does? I think I have an idea but not sure. Any imput will be appreciated.

[Consumer Products Guy]

With capillary GC, a traditional injection size of 0.5 to 5 microliters is usually too much for the capacity of the column, so split injection splits off the majority of the injection away from the column and out the vent line. If the flow through a column is 2 ml/minute, and split flow is 40 ml/min, then the split is 20:1.

[AICMM]

deng74,

Split flow also serves another purpose. It will narrow the band gap on column. If you have a 1 mL inlet liner with 42 mL flow (2 column, 40 to vent) then the residence time of the injected vapor cloud is about 1/40th of a minute. If you run splitless, as the opposite extreme, at 2 mL/min your residence time is about 1/2 minute and you peaks will be broader, especially the early eluting constituents.

Best regards.