Reagent Water Precipitate

[aovaici]

First of all, thank you guys for making these forums, I have already found plenty of great answers on here and it's been immensely helpful!

Now to my question.. Recently I have moved to a new lab and I used to work on a Dionex ICS 2000 (I think from what I remember) which had a eluent regenerator and required DI water and nothing else. I loved it..

Here I am working with three Metrohm systems, which I honestly HATE, but anyways, the question I have is that the machines use a 2% Acetonitrile Solution instead of DI water, which seems to form a precipitate and clog the machines reagent filters every 2-3 days which need to be changed.. costing 50$ a change.. and wasting my time. Is there something I can do to prevent this from precipitating? The Acetonitrile is supposed to act as an anti-bacterial/biological agent from what I've been told by the senior IC guy here who really know or care, and just says to change it.

Thanks a ton!

[Markus Laeubli, Metrohm]

Dear aovaici

What is the 2% acetonitrile used for?
How is the 2% acetonitrile solution prepared? IS it filtrated prior to use?
What is the reason to use 2% acetonitrile?

Please check back with your Metrohm support person or send further information on the system and application to me (lae@metrohm.com).

[aovaici]

It's supposed to be used to inhibit bacterial growth, or so I was told. 2Liters of 18.2 ultra pure water is filled in a 2Liter Jar and 40ml of Acetonitrile is added to it. There is no filtration as there should be no precipitate, though for some reason there is.. this is just a Chemistry question, not relating to metrohm. I will gladly contact you later to ask you questions about your systems and give you a list of complains if you would like to hear about that.

[Markus Laeubli, Metrohm]

I'm not gald to hear about complaints. But I am very fond of supporting to solve compaints. So, do not hesitate to contact me.

[James_Ball]

We have three Metrohm systems and we have never used Acetonitrile as a biocide in the suppressor rinse. We always use only DI water. If you have problems with algae growing in the bottle then just be sure to dump the water out once a week and rinse the bottle with Methanol, let it dry then refill with DI Water. Once ever few months just pull some methanol through the lines or if you get a really bad growth of algae pull some 30% Hydrogen Peroxide through the lines(just not through the suppressor!) and rinse well before resuming DI water flow and starting the system.

We have kept one unit going now for 12 years without ever having to replace the suppressor and it still runs as well as the day we got it. We were replacing the suppressor about every 6-8 months on the old Dionex system we had before this one.