Eluent Degassing Methods - Waters 515 HPLC Operator's Manual

Eluent degassing methods

You can degas eluents using any of the following methods:
• Sparging with helium
• Heating
• Vacuum sonication
Sparging
Sparging removes gases from solution by saturating the eluent with a less
soluble gas, usually helium. Helium sparging brings the eluent to a state of
equilibrium (with respect to dissolved gasses). Equilibrium may be
maintained by slow sparging or by keeping a blanket of helium over the
eluent. Blanketing inhibits reabsorption of atmospheric gases.
Tip:
Sparging may change the composition of mixed eluents.
In-line degassing
In-line degassing removes gasses from the eluent as it passes through a
gas-permeable membrane enclosed in a vacuum chamber. The vacuum in the
chamber accelerates the rate at which the dissolved gas diffuses through the
gas-permeable membrane. This method provides an automatic, continuous
method of removing dissolved gasses, and allows for quick eluent changeover.
Waters makes two in-line degassers: part numbers WAT079700 and
WAT079800. Contact Waters for details.
Heating
Heating to remove dissolved gas is usually not effective unless you boil the
eluent, and this is not practical or safe for mixed, flammable, or volatile
eluents. However, raising the temperature even slightly raises the partial
pressure of the eluent, and thereby reduces the rate of resolubilization of a
gas.
Eluent degassing D-7