Inlet Systems
Split/splitless capillary inlet
Figure
| External | Internal |
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| Septum |
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| Capillary |
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| Plumbing | Plumbing |
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| Septum | ||||||||
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| Inlet |
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| Purge | |||||||||
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| Control | Purge | |
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| IN | OUT | Vent | |||
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| Mass | Electronic |
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| Pressure | |||||||||
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| Flow |
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| Flow |
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| COM | Gauge | |||||||
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| Controller Sensor |
| To | N.O |
| IN | OUT | Split | |||||
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| Solenoid |
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| Back- | Vent | ||||||||
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| Valve |
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| pressure |
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Carrier |
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| Regulator |
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Gas |
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Column
Flow Diagram, Split Operation
Due to short sample residence time inside the inlet, the technique requires rapid volatilization; thus, inlet temperature must be high enough to ensure this.
The backpressure regulator in the split vent path maintains constant pressure at the head of the column. Total inlet flow, controlled by a mass flow controller, divides between a septum purge path and flow down the inlet insert.
Flow through the insert is divided again, between flow into the column and flow around the bottom of the insert, up between the outside of the insert and inlet body, and on to the split vent.
The split ratio is defined as:
Split Ratio =
Split Vent Flow Rate + Column Flow Rate
Column Flow Rate
where flow rates are volumetric, measured in ml/min.
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