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Inlets
Splitless Mode Variables, Practices and Rationales
Parameter Selection/Setting Rationale
Inlet temperature Just above highest boiling point
of solutes (+20°C)
Ensures flash vaporization
Reduce if degradation occurs
Use higher for dirty samples and
higher-boiling solutes
Inlet liner Large volume > 0.8 mL
Small volume < 0.2 mL
Use with autoinjector
Use only for slow manual
injections and gas injections
Inlet packing None Use only with slow injection
Decreases degradation
Silanized glass wool Use for fast autoinjection and
dirty samples
Injection volume 0.5 - 2 µL liquid Depends on solvent, liner and
conditions
Injection technique Fast autoinjection
Hot-needle slow manual
Hot-needle fast manual
Most reproducible
Less needle discrimination
Inject 1 - 2 µL/sec if narrow liner
is used and > 1 µL injection
Use for < 1 µL injections
Purge flow 20 - 50 mL/min Higher if using constant flow
Purge delay time 20 - 80 sec Adjust according to column flow
rate/liner type and sample
conditions
Oven temperature 10 - 25°C below solvent BP Necessary for solvent focusing
Column flow > 2 mL/min when possible Clears inlet fast
Reduces backflash and
decomposition
Septum purge 2 - 3 mL/min Reduces ghosting
Quantification Internal standard
External standard addition
Maximizes reproducibility
Use only with constant injection
volume
Retention gap 1 - 3 m, deactivated
(1 - 2 m per µL injected)
Reduces peak distortion
Promotes solvent and stationary
phase focusing
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