By Anonymous on Tuesday, November 2, 1999 - 11:46 am:
Can someone explain how to calculate the column volume of a 100mmx4.6mm column, I have recieved two formulas:
V= pi r2 L r=
V= 0.5 (L)r2
By Anonymous on Tuesday, November 2, 1999 - 12:49 pm:
A 4.6mm column generally has about 0.11 ml/cm of volume. Your second equation approximates this nicely.
By A.A. on Tuesday, November 2, 1999 - 02:04 pm:
The volume of an empty cylinder is pi r2 L
So 3.14 * (2.3*2.3) * 100 = 1.66 mL
the other calculation 0.5 * L * r2 is an estimation of the column void volume
By tom jupille on Wednesday, November 3, 1999 - 08:52 am:
The second equation should read 0.5 x d^2 x L (where d is the internal *diameter* not the radius).
As pointed out in the preceding post, the first equation gives the total volume of an empty column. The second equation is an approximation (probably +/- 15% or so) for reversed-phase backings based on the assumption that about 60% of the column cylinder consists of mobile phase (basically, this is the interstitial volume plus the volume in the pores).
-- Tom Jupille / LC Resources Inc.
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