Chromatography Forum

well couple days ago I noticed rust around the frit and inside the pump (next to seals);

when I called service they told me that was myfault even if I did not use agressive solvents;

I was so suprised, because I have that system since 1 year and use only acetonitrile, water, methanol and 1% acetic acid; no buffers, no hard acid!!!
I used to wash after every bigger analysis with water, isopropanol etc not to leave any 'bad' solvents inside the pump;

moreover, when i asked what is the pump made of (it should be acid-resistant steel or something like this) and because of 2 years warranty if it is possible to change the pump, the service told me that the pump is not form acid-resistant steel and they will not change the pump;

because I do not come from US, I consider contacting sombody direcly from Agilent from US, so tell me please how can I do that and who I should talk to I would appreciate it very much

Well, I would first put in a formal emailed request for Agilent support to come and inspect the pump under warranty and confirm that the pump is corroding, and that what you are seeing is rust corrosion product.

My suspicion would be that the stainless steel pump head was not fully passivated at manufacture, and it requires a full passivation. If so, what you may be seeing is smut from the slow oxidation of the stainless, which would be fixed by a chemical clean and repassivation.

You have to wonder why your pump is corroding and those used by others are not, and perhaps even whether your applications may require the optional seal wash.

I think it's unlikely they would swap the pump, but they should
1 - examine the pump and rust or smut.
2. Decide what caused it, and formally notify you ( eg service report ). If it is due to manufacturing issues, they should fix it under warranty.
3. Offer a discount if they feel you need some other option or part that was not part of the original package.

In my experience, Agilent have been very good at fixing hardware issues, so you should work though their formal system, starting with you local staff, and escalating the issue through their management as required. .

Please keep having fun,

Bruce Hamilton

But passivation is not permanent, as an example, if you pass Cl- with acetic acid once through the system the passivation can be gone.
Also, I hate to mention this as I have no proof. I have a lot of stainless steel equipment in the lab, once I handled acetic acid nearby for some time. Suddenly rust appeared all over the equipment. The only explanation I had is that some acetic acid and H2O +? repeatedly condensed on the metal in a very aggressive mix. A guess, only.

In short, sure would be surprised if the pump or parts were replaced, sure would like to hear about that if it happens.

I didn't mean to imply passivation was permanent. It's only a more robust oxidation than occurs with air exposure.

The purpose of passivation is to prevent the nasty rust-coloured or black smut that can form on pristine, mechanically-deformed, or heat-affected stainless steels. It also reduces the chance of metal ions being solubilised by most HPLC solvents.

As the colour was around the seals, it suggested to me that inadequate passivation had been performed on the new heads, but there may be several other explanations.

It's very unlikely that diluted acetic acid would corrode the stainless steel much, however corrosion may be greatly accelerated when trace of other acids, including formic, are present. Unpassivated forms of many common ( cheap ) stainless steels can corrode if subjected to high humidity cycles, even without halogens or other initiators - hence the need for good passivation after fabrication..

Bruce Hamilton

Bruce, in turn, I did not intend to imply that passivation doesn´t help, I merely pointed out that it is very easy to remove it, and gave one example. It certainly would be interesting to find out whether the manufacturer exists who covers that in his warranty/guaranty.

Is it possible that there are fumes or vapors present in the area of the pump? I have seen this a number of times on visits to labs. An open container of acid or other. One time I observed an IR spectrophotometer sitting next to open containers of pool chlorine tabs. Needless to say those fumes were eating at the instrument... even stainless steel parts.