Chromatography Forum

hi, i liked know if somebody knows the reason when i select the option "gas saver (20mL/min:1min)" in the chemstation of GC 6890 with MS 5973N, apears an error message "front inlet pressure shutdown" .

Other conditions :
Column: HP-5MS
Column flow:1.3mL/min
Injection type: Pulsed splitless (25.0psi:0.50min; 2uL)
Injector Temp:250ºC
Interface Temp:300ºC

I´ve made all diagnostics, such as Air & water check, and everthing is ok!

tks.

You are not able to maintain pressure in the inlet at the total flow rate used when the gas saver is active. You haven't given any information about column flow or total flow, but I would say that you probably have a rather large leak at the injection port.

There may be two reasons:-

1. Major leak in injection port. Check the septum 'cos repeated injections may lead to septum piercing.

2. Insufficient total gas flow. Check the carrier gas pressure in the gas regulator. Make sure that sufficient inlet gas pressure is set, especially when pulsed splitless injection is used which extra high gas pressure is required.

I don't think there is anything wrong with the gas saver mode in your GC.

When you are running pulsed splitless injections, why do you want to activate the gas saver ?
The gas saver option is for use with split injections. For saving carrier gas after the injection if you use high split flows.
In your case using this option means that you are increasing the gas consumption after the injection and the initial pressure is not sufficient to deliver 20 ml/min through the split vent.
Do not select gas saver option with pulsed splitless or splitless injections.

When you are running pulsed splitless injections, why do you want to activate the gas saver ?
The gas saver option is for use with split injections. For saving carrier gas after the injection if you use high split flows.
In your case using this option means that you are increasing the gas consumption after the injection and the initial pressure is not sufficient to deliver 20 ml/min through the split vent.
Do not select gas saver option with pulsed splitless or splitless injections.

Tanks...

You might want to use gas saver on splitless injections. After the splitless sampling time the inlet is switched over to split mode to flush any residues out of the liner. I often use a high split flow initially, 50 mL/min for example, to flush out the liner, then drop the split flow down to 15 mL/min to minimize gas use.

i think the resean in gas saving >total flow ,so the sation give your warnning ,after that it will shut down auto .

i think the resean in gas saving >total flow ,so the sation give your warnning ,after that it will shut down auto .

Agilent labels the command as Gas Saver, but it is really a command to change the split ratio. It doesn't matter if the total flow is higher or lower than the original setting, the gas saver setting will overwrite the original value.

thank you !i think if the gas press is low also can cause this .