Chromatography Forum

Hello,

my question is as follows:

According to the HP manual, the regulator should have a stainless steel diaphragm. What would the disadvantage or problem be if a brass regulator was used without a SS diaphragm? Is there anything one should particularly pay attention when choosing a regulator for the air supply of the FID?

thanks

Hello
I think, that the regulator should have a stainless steel diaphragm, but not resine/ plastic diafragm . For minimisation organic compound in air.

And should, but not must

If you use a regulator with a polymer diaphragm it will continuously bleed organics into the air supply, giving a higher background signal and more noise. These can be removed with a charcoal filter.

Peter

Well I think a SS regulator is what I will be getting for my air.

Another question here.

For the FID detector I notice RESTEK recomments purifiers for MOISTURE, H/C and OXYGEN for the carrier gas.

For the make up gas and Hydrogen they recommend MOISTURE and H/C. I also notice that some just use H/C for the FID support gases. Is it crucial that moisture gets removed too??

quoted: "Is it crucial that moisture gets removed too??"

Same reason not to use brass parts for analytical applications:

corrosion occurs when water is present, or at least it is often accelerated.

SS parts are best.

Dry gases are best.

No corrosion is best.

No fouled components due to junk from corrosion in the system is best.

Are we all on the same page now?

Good for us all.

Rod

Well I think a SS regulator is what I will be getting for my air.

Another question here.

For the FID detector I notice RESTEK recomments purifiers for MOISTURE, H/C and OXYGEN for the carrier gas.

For the make up gas and Hydrogen they recommend MOISTURE and H/C. I also notice that some just use H/C for the FID support gases. Is it crucial that moisture gets removed too??

I do not understand this "economy". Put all the traps. In our institute because of the water in the air "flow regulator" to 7890 "covered himself with a copper basin". The result - $ 1000, half of the year "bureaucratic war" on the guarantee obligations of the parties and payment. And two months for the supply valve block from the Chinese plant to service firm.

Use the traps. Get the best gas quality you can possibly fight for.

The majority of problems encountered by GC users are caused by improper gas supply. Whether its something quick (gas supply contaminated with hydrocarbons will cause immediate problems) or slow (trace amounts of moisture and hydrocarbons will eventually gum up the mechanisms and frits contained in modern electronic pressure controllers) you will eventually be paying for your "savings" if you neglect filters and high quality gases.

thanks for the info!