Agilent Technologies G4782A, User Manual

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58 1260 SFC Binary Pump
4
Optimizing Performance
When to Use a Vacuum Degasser
When to Use a Vacuum Degasser
A degasser removes air, which is dissolved in any solvent. When solvents are
heated or mixed with other solvents, air can leave the solvent and form small
bubbles. Over time, these bubbles accumulate and can cause pressure
fluctuations which may finally result in retention time shifts.
All Agilent 1200 Infinity II Series Pumps have a built-in degasser. While a
degasser is needed for low pressure mixing pumps like Agilent quaternary
pumps, high pressure mixing pumps like Agilent binary pumps are more
robust with respect to bubble formation. However, a degasser is recommended
for best performance.
Additionally, a degasser is highly recommended for the following applications:
• Your detector is used with maximum sensitivity in the low UV wavelength
range.
• Your application requires highest injection precision.
• Your application requires highest retention-time reproducibility (flow rates
below 0.5 mL/min).
• The binary pump is used with bypassed damper and mixer.
The external 1260 Infinity II Degasser G7122A is recommended for use with
applications using highly volatile solvents like Hexane or DCM, solvents with
special characteristics like THF, or applications using refractive index
detection.
Operational Hints for the Vacuum Degasser
If you are using the vacuum degasser for the first time, if the vacuum degasser
was switched off for any length of time (for example, overnight), or if the
vacuum degasser chambers are empty, you have to prime the vacuum degasser
before running an analysis. Priming is usually done by pumping at a high flow
rate (3 – 5 mL/min). Alternatively, a syringe can be used to draw the solvent
through the (empty) degasser if the pump does not aspirate the solvent by
itself.