VacuumPump
Eluent
Controller
Degassing
Chamber
HPLCPump
Injector/
Auto
Sampler
ToVacuum
Controller
ToVacuum
Pump
Degassed
EluentOut
Eluent In
Dissolved
Gas
APPLICATIONNOTE
WhyDegasYourMobilePhase?
Dissolvedair inHPLCmobilephases can result inflow rate instabilityand
baselinedisturbance.
Flow rate instability:
Non-degassedmobilephasecanoutgas in the
pumphead, causingbubbles tobe formedand trapped inside thehead
or check valves. Thesebubbles cancauseflowdisturbancesandpressure
fluctuations, resulting inflow rate instability.
Baselinedisturbance:
As themobilephasepasses through thecolumn,
it experiencesa largepressuredrop.Non-degassedmobilephasecan
outgasdue to thispressuredifferential, causingairbubbles to form.
Airbubblespassing throughor lodging in theflowcell causedetection
disturbances, exhibitedasbaselinenoise.
WhyUseaDegassingSystem?
Helium sparging isacommonmeansof degassingHPLC solvents. This
methodhas itsdrawbacks, however.Helium tanksareexpensiveand
bulky, and solventbackupandcontaminationareconcerns. Inaddition,
helium spargingcanchange thecompositionof apremixedmobile
phaseover time, due to thedifference in theevaporation ratesofmobile
phasecomponents.
Incontrast, theSystec
®
DegassingSystemhasnoneof thesedrawbacks,
and it isextremely fast andefficient at removingdissolvedgases—more
efficient thanhelium spargingor PTFE-baseddegassing systems.
TubingConnections
We recommendETFE tubing (page73) beused to limit regassing
ofmobilephasebetween thedegasser and yourpump. ETFE is
recommendedbecauseof its superior impermeability togases
(compared toPTFE, FEP, andPFA tubing).Applicableflangelessfittings
for 1/8”OD tubingare foundonpage26.
GPCandHFIPApplications
Standarddegassingchambers,withPEEKbulkheadunions, are
not recommended forGPCapplicationsor for usewithHFIP
(hexafluoroisopropanol). SpecialGPC“hardened” versionsareavailable.
Pleasecontact us formore information.
Dissolvedgasesareactively
removed fromaflowing liquid
streamby vacuum via the
SystecAF
®
membrane.
TYPICALDEGASSER IMPLEMENTATION
DEBUBBLERS&DEGASSERS
177
Debubbler Series
