Chromatography Forum

I know that I can modify the amount of analyte that goes onto column via varying the split ratio at the injector side; howeer, can the amount of analyte vapor that is transferred via the Transfer line be varied? To my understanding the headspace oven always injects 1 mL of vapor---then on the GC side you can change the volume by adjusting the split ratio on the inlet. But do anybody know how to increase the amount of vaporized sample from the HS oven?
The reason this question is important is I want to get beter signal to noise at a split ratio of 1. How can I make the HS oven side inject > 1 mL of vapor?

Install a larger loop on the six-port valve. Larger volumes will not necessarily improve detectability of low concentrations; unless you take steps to focus the analyte at the head of the column, by temperature programming for e.g. the peaks get wider but not higher.

Peter

You can increase Headspace Oven temperature to get a better signal, split ratio can be down to 0.5:1.

Are you using a fixed loop valve injection, or a timed flow injection (Agilent or PE?)

The correct answer depends upon your response to that question.

Rod