2.3 Sample volume
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IC equipment: Inline Ultrafiltration 2 - push mode
2.3
Sample volume
The sample volume depends on the following factors:
￭
Volume of the sample needle
The lower the volume of the sample needle, the smaller the required
sample volume.
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Length of the capillaries
The shorter the length of the capillaries, the smaller the required sam-
ple volume.
￭
Inner diameter of the capillaries
The smaller the inner diameter of the capillaries, the smaller the
required sample volume.
￭
Volume of the peristaltic pump tubings
The lower the volume of the peristaltic pump tubings, the smaller the
required sample volume.
￭
Volume of the ultrafiltration cell
The lower the volume of the ultrafiltration cell, the smaller the required
sample volume.
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Volume of the sample loop
The lower the volume of the sample loop, the smaller the required
sample volume.
￭
Ratio of the flow rate on the sample side to the flow rate on the filtra-
tion side
On the sample side, a high flow rate is required to pump a high sample
volume through the sample chamber. On the filtration side, a lower
flow rate is required as less filtrate needs to be pumped through the
filtrate chamber than sample through the sample chamber.
The smaller the ratio of the flow rate on the sample side is to the flow
rate on the filtration side, the smaller the required sample volume.
The pull mode and the push mode differ with regards to the length of the
capillaries and the volume of the peristaltic pump tubings. The volume of
the peristaltic pump tubings in particular carries weight.
Due to the additional volume of the peristaltic pump tubings, the required
volume is considerably higher in the push mode than in the pull mode.
