Gold seal in pump

[alcorn]

Hi all,
What is the purpose of using gold seal in HPLC (Agilent 1200) pump outlet valves (actually in ball valve and purge valve)? Why its not used in other parts? I read somewhere gold is used for its low chemical activity, If so, why chemical activity is important only in purge section and not in other parts such as column inlet?

[tkubowicz]

Hello

It is more about gold inertness (You will not see rust on gold seal ). Gold seal separates two parts (valve and pump head). You can minimize "contact" between them.
Of course ideally all parts in flow path should be as inert as possible...but think about LC cost then

Regards

Tomasz Kubowicz

[Gerhard Kratz]

It makes no sense, but maybe this seal is a little bit more expensive than made from other, usual materials.

[KM-USA]

Gold is also soft, so can seal well. We re-used these seals several times typically.

[James_Ball]

It is because it is soft and inert. Other materials which would be used in this manner would be lead, copper and aluminum, all of which would be degraded by an acidic mobile phase.

When Waters first introduced their UPLC it used gold ferrules to seal the columns to the tubing.

[BostonFSE]

Good question. The gold seals are changed during each PM but its really unnecessary. Ive never fixed a problem that was caused by a "bad gold seal"- just clean with IPA.
They are also the same gold seals on the outlet ball valve (check valves)
The "old" gold seals are heavier (no swirl pattern) and are worth more than the new ones.
Never throw them away,save them up. The newest ones, 1260, 1290 are embedded in the valve.