Acid Contamination on ECD

[MarkRob]

I'm wondering which way to proceed.

We've accidently intorduced acid (H2SO4) in to our system because of an acid clean up.

Will baking the detectors for a long time get them back to a workable level? Do I need to send my ecd's in?

any help is appreciated.

thanks

[Suresh Seethapathy]

Mark,

With the little i know from what you have posted, baking would be the last thing i would do (if at all i do it!). Sulphuric acid has a boiling point of about 290 centigrade, and with a little bit of moisture around when baking you will only end up eating up the metal parts in the detector.

You might want to check the safety procedures of your company. Most safety departments in a company wont be happy if you play around with radioactive sources. Which model/make ECD are you using? If it is something like Thermo GC's, you can actually remove atleast the counter electrode and clean it with some solvent. If it is something like Agilent's uECD, i am not quite sure how it can be handled.

Good luck fixing the ECD!

Suresh Seethapathy

[MarkRob]

Just an update of this problem.

I didn't get the suggestion to NOT bake out until today when it was too late.

Maybe I can re-define what happend. Our prep person wasn't as careful about one of the hexane extracts which we used an acid clean up on. She introduced acid into the auto sampler vial. the auto sampler picked up the acid. We're talking about 1 ul of acid in the system.

I baked overnight and ran about 10 MeOH samples to try and get the acid out. It seems to have worked. Our ECD's have come down. But I think that the columns are fried.

ECD's are close to what they used to be not perfect.

that's all for now

[Suresh Seethapathy]

Glad that the ECD is working fine now. If introduced into the GC the way you have described, I doubt if the acid actually made it to the detector. It probably reacted with everything on its way and the ECD baseline was probably the reaction products - acid with stationary phase. When you baked the ECD, you probably cleared this junk out.

But just to make sure, perhaps its a good idea to clean/change/deactivate the liner.

Good luck.

Suresh Seethapathy.

[AICMM]

MarkRob,

Couple of comments. I would swipe around the ECD's and have them counted. Probably not an issue based on what you have written but much better safe than sorry. Also, much less liability knowing you have not leaked than finding out later.

Second, I would trim a couple of meters off the column and see if that does not help baseline and PCB response. Third, I would florisil column cleanup every acid digested extract to ensure this never happens again. Micro-columns from pipettes with florisil are cheap insurance and did not ever affect my recoveries in the past.

Best regards.