Flow rates on an Agilent 6890

[mdooley]

Have a method for caffeine analysis and it says to use a flow rate of 10ml/min
this sounds high to me
Any suggestions guys
MD

[walter]

Depends on the column , packed or capillary, id, etc.

[GasMan]

It can also depend on the carrier gas. Using hydrogen allows higher flow rates.

Gasman

[mdooley]

Hi Guys
Its a Capillary column (HP -17 from J&W Agilent) carrier gas is Nitrogen detector is FID
Thanks

[Johnny Rod]

What is the diameter of the column?

Depending on how easy the separation is you can go away from the ideal flow to speed things up, this could be one reason for the flow rate given. Or it could be wrong.

[Peter Apps]

Have a method for caffeine analysis and it says to use a flow rate of 10ml/min
this sounds high to me
Any suggestions guys
MD

Maybe that's the total flow; 1 ml down the column and about a 10:1 split ???

Peter

[Bigbear]

Could be all of the above. I used about 10 cc/min with a 30M X 0.53 column. Worked fine for years. Switched to a 0.45 column and reduced the flow down to about 7.

Depends on the column ID.

[mdooley]

thanks guy for your help
MD