The effects of inlet liner configuration and septum purge flow rate on discrimination in splitless injection
✍ Scribed by Hinshaw, John V.
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 691 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0935-6304
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✦ Synopsis
Abstract
An unmodified split/splitless inlet system using forward‐pressure controlled pneumatics was operated in splitless injection mode with several inlet liners under a range of septum purge flow rates. The relative recovery (discrimination) of hydrocarbons ranging from n‐C~8~ to n‐C~20~ depended strongly upon the injected sample volume with open‐ended liners at high septum purge flow rates of e.g. 50 mL/min. Little or no discrimination was observed at septum purge flows of 2–3 mL/min. The same inlet was also operated in a back‐pressure regulated configuration that produced mass discrimination similar to that observed with the higher septum purge flows in the forward‐pressure configuration. An inlet liner with a restricted inlet and outlet gave mass‐discrimination levels independent of septum purge flow rate, but in the reverse sense of that observed with open‐ended liners. Preferential volatile‐component losses out of the inlet liner to the septum purge vent are principally responsible for the observed mass discrimination with openended liners, while mass‐dependent losses with doubly‐restricted liners seem due to slow sample evaporation.