Chromatography Forum

Hi,

I have a Waters Delta 600 pump. It generally works like a charm and recently had a PM tune up. This is a very busy period of time in my lab. I realized yesterday that I have an outlet check valve that is not behaving properly and unfortunately do not have a replacement on hand to swap in. I am trying to avoid a delay in instrument duty while the replacements valves are on order. I determined which valve was giving problems with the ramp test. I took out the offending valve and sonicated in MeOH for several minutes, but this didn't fix the problem. I will sonicate longer in MeOH and then in HPLC grade water.

Two questions:

1. What practical tricks do you use to try to get check valves working?
2. What are your preferred commercial sources for replacement check valves?

Thanks in advance,

Dave

Waters, Upchurch Scientific, Optimize Technologies - and others all make wuitable cartridge check valves for that pump. See who can get one to you fastest.

We use sonication in hot water (> 60°C), followed by sonication in acetone, followed by methanol.

hot water for buffer removal
acetone for acetonitrile film removal
methanol for good lubrication


Ace

Thanks aceto for suggesting this sonication protocol. How long do you sonicate in each solvent? Thanks, Dave

about 10 minutes each.
We have a beaker where we collect our bad checkvalves (we have a lot of spares).
When someone has some time, we sonicate them all together according to the protocol described.

Ace

Thanks. What you describe makes a lot of sense. I am a professor of chemistry at a university in Georgia. What type of lab are you in?

pharma

My research student followed this protocol and the check valve is operating properly again, as verified by ramp test. We are up and running again, but this made me aware of the risk to productivity of not having some spares in stock. Will order soon (will check with Restek, our main supplier of chromatography consumables)
-Dave

In the Alliance equipments, I was tought to sonicate check valves in HNO3 10% for 10 minutes, and then wash it by sonicating 3 times in water for 15 minutes. Tough I wouldn´t recommend it for valves who have plastic pieces.