Chromatography Forum

dear friends,

what's the maximum rate (mL/min) that and C18 HPLC column can take?

the pump gives us the maximum of 9,999 mL/min. What'd happen if I run a sample at such rate?

Thanks

depends on the pressure the column can tolerate, and this pressure is a funcion of flow so....

dear friends, what's the maximum rate (mL/min) that and C18 HPLC column can take?

The pump gives us the maximum of 9,999 mL/min. What'd happen if I run a sample at such rate?
Thanks

Depends on the column and the chromatograph. You would not get close to 9.999 ml/min with a column in place as the max pressure would be exceeded (9.999 would only ever be used to flush the system to waste)However if you tried you could:

Collapse the stationary phase of older columns
Cause the pump seals to blow/leak on Older chromatographs
Blow any PEEK fittings.

Generally, on a normal HPLC I wouldn't take the preesure above 3000 psi and flow genrally ~2 mL/min.

"You would not get close to 9.999 ml/min with a column in place as the max pressure would be exceeded" - I will just quote someone in response to this comment - "Depends on the column and the chromatograph"

What size column (length and internal diameter) and what particle size?

Just because a pump is rated to 10mL/min doesn't mean it can supply 10mL/min at a sensible working pressure for days without breakage. Many pumps can do 10mL/min for purging purposes, at low pressure, for even an hour or two, but would collapse completely if you tried to use them as preparative pumps for real chromatography at that sort of flow rate, with pressure, and for days.

What size column (length and internal diameter) and what particle size?

Underivatised Silica:
particle size: -------------------- 5 micrometers
Pore size: ----------------------- 100 Angstrons
pore volume: ------------------- 1.0 ml/g
Surface area: ------------------- 300 m2/g

Derivatised silica:
carbon content: ----------------- 15.5 %

Column:
Packing ---------------------------- ACE 5 C18
Lenght ----------------------------- 25 cm
Internal diamenter -------------- 4.6 mm

Thanks

I believe that kind of column should be ok up to 4000 psi, you can find that kind of info in column manual (attached in the box)

Depending on the solvents used (viscosity) up to 2 mL/min should be achievable