When using a GCMS duel column, when using one column at 1.2ml/min what should i do for the second column if it's on a deans switch (do i keep at same flow or lower? my service engineer has said drop it to 0.1-0.3ml/min but im scared of dmg to column

Hi

To keep column in good situation when not in use, there should be some minimum flow like .5 or .3.

1. It's upto you that you want to save carrier by using minimum column flow or same flow.Main thing is that there should be some flow.

they both currently feed into MSD, does it matter if i have at .5 versus equal flow?

Hi

You are saying that you are using dean switch.

Generally dean switch is flow cutting technolgy to cut the flow in primary n secondary column connected with different detector.

Now you are saying that both column is connected with single MS detector.

So if you have some specific application then keep flow as per your application during run.

Hi

You are saying that you are using dean switch.

Generally dean switch is flow cutting technolgy to cut the flow in primary n secondary column connected with different detector.

Now you are saying that both column is connected with single MS detector.

So if you have some specific application then keep flow as per your application during run.

sorry bit of a novice, it's a two way splitter for two columns into one msd transfer line i guess. We only ever use one column at a time - i just dont want to damage a column by taking it up to temp whilst not in use.

Hi 

I guess that one column is connected with MSD and second column with any other detector..

both feed the detector, i will have it so one column is 1.2 and the other 0.3 so total flow to MSD is 1.5

Can you share picture of oven and columns connected with detector..

Hello it is better to have some extra flow coming from the pressure control module. i.e. C1 - 1.0,  C2 - 0.3, R - 1.5 or something similar. Reason being better pressure control at the splitter.