Flow rates

[Agidora]

Hello, I am currently trying to set up our HP 5890 II to use for ASTM 6584 to test biodiesel. I was wondering what would be the recommended flow rate for the air, and the hydrogen and helium (make up gas). We are using He as the carrier gas and we know that to be 3ml/min for the flow but are unsure what to use for the other flows. Is there any recommendation from anyone who does this, or a similar method?

thanks,

Andrew

[Rick]

Hello!
For FID application:
Air: 350ml/min
Hydrogen:35ml/min
Make-up + column flow:30ml/min

[skunked_once]

The operator's manual for the 5890 series II calls for hydrogen flows of 30 mL/min and air flows in the range of 375 to 425 mL/min. These are starting points and can be adjusted up or down as required. I am currently using flows of 35 mL/min for hydrogen and 345 mL/min for air. Don't forget to set the detector makeup gas flow also. I use 35 mL/min. helium for makeup.

[GasMan]

All of the above replies are correct. However, with the price of helium, you may want to consider using nitrogen as the makeup gas. It is much cheaper, and you will see a slight increase in sensitivity.

Gasman