6
Inlet Liners for Split Injections
Split liners are designedwithmixing chambers and tortuous flow paths, to fully vaporize the
sample into a homogeneous vapor cloud before it reaches the split point.All Restek split lin-
ers are fully deactivated using a high-temperature silanizing reagent. This caps surface
silanol groups so active compounds in the sample do not degrade or adsorb onto the hot
glass surface.
To trap non-volatile residue and prevent column contaminationwhen analyzing dirty sam-
ples, pack split linerswithwool, CarboFrit
™
packing, or fused silica beads. Some of the
more commonly used inlet liners are described below.
A) Split Liner withWool
The wool provides a large surface area to allow
rapidvaporizationof the sample anddeliver a uni-
form vapor cloud to the split point. The lowmass
of thewool fiber promotes complete vaporization.
Benefits:
•
Low cost.
•
Reproducible performance.
Drawbacks:
•
Wool can be adsorptive, especially if fibers are
broken.
•
Highmaintenance requirements.
B) Laminar Cup Splitter
The sample flows through a small opening and en-
counters the head of the elongated glass cup. It
then travels around the outside of the elongated
cup before the flow is inverted twice. Larger vol-
ume injections are possible because the liquid is
trapped at the inner base and cannot escape until
vaporized.
Benefits:
•
Recommended by chromatography expert
Dr. KonradGrob
1
.
•
Best splitter liner for highmolecularweight
compounds.
•
Laminar flow profile provides highest
resolution.
Drawbacks:
•
Costly.
C) Frit Splitter
The samplemust pass through the porous ceramic
frit. The high surface area and tortuous flow path
ensure complete vaporization.
Benefits:
•
Traps septum particles and residue.
Drawbacks:
•
Ceramic frit can be active.
•
Difficult to clean.
D) Cup Splitter
The sample flows through a mini funnel and en-
counters a glass cup. The flow path then inverts
twice before reaching the split point.
Benefits:
•
Tortuous flow path aids in sample vaporization.
•
Minimizesmolecularweight discrimination.
•
Can be packedwithwool to trap particles.
Drawbacks:
•
Difficult to clean.
E) Cyclosplitter
®
(Patent #: 5,119,669)
This patented design incorporates a cylindrical
glass spiral in the sample pathway, providing a
large area for sample vaporization.
Benefits:
•
Ideal for dirty samples.
•
Allowsmany injections of dirty samples before
cleaning is required.
•
Easy to clean.
Drawbacks:
•
Not recommended for large volume injections.
F) Baffle Splitter
The baffle induces turbulent flow that directs the
sample against thewall of the glass liner.
Benefits:
•
Reproducible performance.
Drawbacks:
•
Prone tomolecularweight discrimination.
•
Septum particles and residue can enter column.
•
Subject to incomplete vaporization.
1
“InjectorsProvidingCompleteSampleEvaporationAbove theColumnEntrance inVaporizingGC Injec-
tions,”K. Grob andC.Wagner,
HRC&CC,
Vol. 16, p. 429.
A
B
C
D
E
F
010 %
deactivated
all liners are
See page 17.
All Restek liners are deactivated to prevent
adsorption of active compounds. Call for
information on custom deactivations.
