Thermo Scientific EASY-nLC 1200 Troubleshooting And Maintenance Manual page 159

Introduced Swept Volume
Thermo Scientific
Normally when solvent B (95% acetonitrile with 0.1% formic acid) reaches the column, the
backpressure measured by pressure sensor A drops to less than one-half the amount measured
for solvent A (water with 0.1% formic acid) alone. If the backpressure does not drop by more
than 50 percent when solvent B reaches the column, the solvent system might contain an
additional swept volume introduced by poor tubing connections.
The additional swept volume increases the gradient delay volume so that the gradient reaches
the column later.
Figure 116 shows the pressure dip that occurs when the gradient starts to reach the column.
Figure 117 shows the pressure dip for the sample chromatographic method, but occurring
two minutes later due to the added gradient delay volume.
Figure 116. Normal pressure dip for pressure sensor A as the gradient reaches the column
The pressure starts
to drop at approximately
25 minutes as 100%
solvent B reaches
the column.
EASY-nLC 1200 Troubleshooting & Maintenance Guide
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Troubleshooting
Troubleshooting Tips
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