HPLC HINTS & TIPS for
Chromatographers
Tip# 106:
Determination of HPLC Column Dead Time (T0):
Column Dead Volume or Time (AKA: Column
Void/Dwell Time) is the column volume divided by the flow rate and is usually expressed in
minutes. Determining T0 is necessary to find the Resolution Factor (K1)
in a separation. Ideally, it is
determined by injecting a sample which is unretained by the column and recording the
retention time. It can also be calculated if you know a few physical specifications of the
column and media used. Here are some common values based on typical HPLC column dimensions
used today. At a flow rate of 1.000 ml/min these values would also be the time in minutes.
|
COLUMN DIMENSIONS (I.D. x Length
(mm)) |
|
VOID VOLUME (ml) |
|
|
|
|
|
|
|
|
|
|
|
|
2.1 x 100 |
|
|
|
0.24 |
|
|
|
|
2.1 x 150 |
|
|
|
0.37 |
|
|
|
|
2.1 x 250 |
|
|
|
0.61 |
|
|
|
|
2.1 x 300 |
|
|
|
0.73 |
|
|
|
|
|
|
|
|
|
|
|
|
|
4.6 x 100 |
|
|
|
1.16 |
|
|
|
|
4.6 x 150 |
|
|
|
1.75 |
|
|
|
|
4.6 x 250 |
|
|
|
2.90 |
|
|
|
|
4.6 x 300 |
|
|
|
3.49 |
|
|
|
|
|
|
|
|
|
|
|
|
|
10.0
x 100 |
|
|
|
5.50 |
|
|
|
|
10.0
x 150 |
|
|
|
8.25 |
|
|
|
|
10.0
x 250 |
|
|
|
13.75 |
|
|
|
|
10.0
x 300 |
|
|
|
16.49 |
|
|
|
|
|
|
|
|
|
|
|
Note : Assumes an Average Pore
Volume of 0.70 (check with the manufacturer for actual values).
Void
Volume (ml) = (d^2 *Pi * L * Pore Volume) / 4 ; *Column Diameter & Length are in cm. |
> Bill Letter, 08/01/10.
HINT's & TIPS
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