Chromatography Forum

Hi guys.the ion gauge read 8.8 *0.000001 torr (it should be between 3-5). the MS pressure is 63 mtorr. water and nitrogen and oxygen are in good percentage to the 69 so I am assuming there is no leak. but why this high pressure and why there is no flow from the septum purge valve, I think it should be 3mL/min helium gas.

we had something similar,

turned out to be the filter for the split flow.

have you tried blocking the injector with a blind ferrule (I am assuming you have a SSL) and see if the septum purge still does not deliver?

M

[quote="Mikaelalfredsson"]we had something similar,

turned out to be the filter for the split flow.

have you tried blocking the injector with a blind ferrule (I am assuming you have a SSL) and see if the septum purge still does not deliver?

M[how can I locate it ]

What type of GC do you have?

if you have an electronical controlled GAs flow unit, when blocked you should be able to read out if your GC thinks it has a Septum purge.

also if you have a flowmeter, put it on the outlet of the septum purge, and the split vent and see if the flows are correct.

usually the electronic gas flow control contains both filters and Valves. if one is not working or clogged --> problem

Do you see any of the m/z 207, 429, 355, 281, that normally indicates a septum bleed? or possibly a none working septum purge?

What type of GC do you have?

if you have an electronical controlled GAs flow unit, when blocked you should be able to read out if your GC thinks it has a Septum purge.

also if you have a flowmeter, put it on the outlet of the septum purge, and the split vent and see if the flows are correct.

usually the electronic gas flow control contains both filters and Valves. if one is not working or clogged --> problem

Do you see any of the m/z 207, 429, 355, 281, that normally indicates a septum bleed? or possibly a none working septum purge?

Another thing.

If you have ECP try going in the valves section on your GC panel and turn the septum Purge valve on/off a couple of times.

that just might be the quickfix for ya..

This is all assuming you have an Agilent GC

Measure your split and septum purge flows. Replace the split vent trap, and you may also want to remove the ALS tray (if you have one.) Once that is off remove the screws holding the greenish cover around the inlets. This will expose the split vent line (1/8th inch copper tubing connected to inlet and split vent trap.) This may be clogged as well and can be cleaned by squirting something like methylene chloride through it or simply replaced if you have tubing and swagelok nuts.

You may also want to check the 'port' where the line attaches to the inlet. If you remove the inlet liner, gold seal, and column and then stick a beaker under the inlet you can squirt solvent through here to clean out any gunk hanging around right there.

If these areas are clogged the EPCs are unable to accurately achieve pressure and thus cannot calculate flows correctly. Very common problem.

[Hi, I have a Agilent 5890 II plus. I tried every thing possible that including, changing the proportional valve, solenoid valve, cable position but with out any success, I didn't change the EPC unit yet, Also i check out all the tubing and they were fine] What type of GC do you have?

if you have an electronical controlled GAs flow unit, when blocked you should be able to read out if your GC thinks it has a Septum purge.

also if you have a flowmeter, put it on the outlet of the septum purge, and the split vent and see if the flows are correct.

usually the electronic gas flow control contains both filters and Valves. if one is not working or clogged --> problem

Do you see any of the m/z 207, 429, 355, 281, that normally indicates a septum bleed? or possibly a none working septum purge?[/quote]

if your flow meter does not give you any reading out from the septum purge vent.

then probably the EPC needs to be changed,

M

[quote="Mikaelalfredsson"]if your flow meter does not give you any reading out from the septum purge vent.

then probably the EPC needs to be changed,

M[Will change it and let you know, thanks a lot for the help ], Can you point to me which one

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