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Topic: precipitates in my sodium acetate tetrahydrofuran buffer  (Read 1699 times)

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Offline Tina Lin

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precipitates in my sodium acetate tetrahydrofuran buffer
« on: November 14, 2012, 04:36:01 PM »
Hi,

I've been using this buffer (20 mM sodium acetate trihydrate, adjust to pH 7.1; add to final 0.3% tetrahydrofuran) for my OPA-amino acids analysis. Sometimes I observe white precipitates in this buffer after it has been sitting in the lab for more than a week. When I see visible precipitates, I'll filter the solvent again. However, I worry about the precipitate may have formed inside my column and that is the reason that my column (Hypersil Gold, 3 uM, 2.1*150mm) got clogged last night. This column is relatively new, only pass less than 300 injections to it. I also have a guard column in front of this analytical column.

Can anyone tell me
1. if the precipitate could have formed inside my column and cause my column to be clogged? 
2. What is this precipitate?
3. How can I try to restore my column?
4. What can I do to prevent the precipitation to form?

Any response will be highly appreciated.

Tina

Offline Arkcon

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Re: precipitates in my sodium acetate tetrahydrofuran buffer
« Reply #1 on: November 14, 2012, 06:14:58 PM »
There's lots of questions here, we'll try to tackle them all.

I don't know what this precip is.  It seems to be a typical aqueous solution, with just a trace of organic additive, so it should be stable indefinitely.  I'm assuming you've prepared it with HPLC grade water and solvent, and you filter the sodium acetate solution after preparation, and you've kept the eluent free of dust.

As for precipitation within the column, that can be a very diverse problem.  Sure the same precipitation can happen in the column as happened in the bottle.  But maybe you've gotten the precipitation for another reason.

First off, check the the system without the column is clear.  You might try replacing the guard column, if you think there's a blockage, it should be there.  Thing is, if the method is very aggressive to the column, or the samples are very dirty, a column may only last 300 injections.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

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