Chromatography Forum

Hello,
We have some trouble with Divert/Inject valve. Some methods have setted 2 or 3 steps for this valve but they are not working. After step 1, valve is not diverting and all sample is being injected. As result we have to clean several time the equipment. Any comment is wery welcome. Thanks . Sonia

Hi Sonia,

Just to clarify, by entering a Start and End time and checking the Enable Divert Valve box in the Options>Solvent Delay window, switches the flow to waste.

Let's say your peak of interest is at 4 minutes. Your first solvent delay might Start at 0 minutes and End at 2 minutes. During this time your solvent stream will go to waste. At 2 minutes there will be an audible noise from the divert valve as it switches and the solvent will then flow to the detector. After your analyte has eluted your second solvent delay could Start at 6 minutes and End at whatever time your method ends.

Does that make any sense? From what I interpret from your original post you may be expecting the reverse to happen. You're setting the times you don't want your sample to be injected.

Hi Richie,
Thanks for your answer. After my peak was eluted ok, the 2º delay solvent is not working. So, my peak eluted at 4.5 min and the rest is reaching the MSMS, no waste. It is a mess. I don`t know why Valve is not responding the 2º step. Has it any sense? I`m wondering if software is responsible...or maybe valve is failing?

Hello again,

If you can't hear it switching then you probably ought to get someone out to have a look at it. As you said it may be a software issue or a connection problem.

It shouldn't be too difficult to replace the stator face and rotor seal in the valve. Although I don't know if Waters make them available. So you might have to call them out for that as well.

Hi,

We sometimes face such valve issues on our Waters instruments. Usually it comes either from a corrupted MS method or from a communication issue. In the first case, you can try to create a new method from scratch and see how it goes. In the second case you may reset the electronics of the MS (I don't know if it is feasible on the Quattro premier without venting). The fact that the valve switches a first time but not a second suggests that the hardware is not damaged and rather points to a communication issue.

Hello! thank you very much for your comments. I will try what you suggested. If I'm able to solve it I'll write here to share with you.