Any experience of changing Agilent MCGV?

[Anthony_Ng]

One of our multi channel gradient valve (MCGV) in Agilent 1050 leak (Channel A). Should I change the whole set or I can replace the solenoid A only?

By the way, is MCGV for 1050, 1100, 1200 are the same?

[Consumer Products Guy]

The multi-channel valve is pretty eay to swap out; but I don't think there are any user-available parts for it. It sells as an exchange unit, nets about $600 last time we got one (you ship the old one back for credit), and it's been a while. I've got four 1050 systems and four 1100s, their MC valves are different (don't know about 1200s, you could look up on Agilent's site). Yes, if you have a leak, it's bad. So ALWAYS fix first what you KNOW is bad; I saw your other post about your HPLC issues, may all be related to this.

[Anthony_Ng]

Thanks Consumer Products Guy.

More problems discovered today. The active inlet valve (AIV) gold seal and cap disappeared!!! Some previous groupmates forgot to replace a new one in it (5years ago).

Hence I borrowed a pair from other research group. And used Channel B/C/D only. The baseline variation reduced from 100mAU to become 10mAU now. (Is it ok if I keep this MCGV but not using the leaking Channel A?)

Then I disconnected the tubing from pump to flowcell. Set it to higher flow rate (3ml/min). I saw the flow is not a continous stream, but as a stream for first stroke and droplets for the second stroke.

I suspected there is blockage in the inlet/outlet check valve. And 1050 AIV is "all-in-one" design! There is no cartridge inside the AIV as 1100/1200. Of course, I cannot drop the whole AIV into solvent and sonicate it.

I phoned Sevice Engineer and he suggested to run the system with 3N nitric acid, hoping that dirt will be washed off. I didn't try yet becasue it is already day-end today.

[Consumer Products Guy]

used Channel B/C/D only. The baseline variation reduced from 100mAU to become 10mAU now. (Is it ok if I keep this MCGV but not using the leaking Channel A?)

I'd replace the whole MC valve.

The 1050 AIV is "all-in-one" design! There is no cartridge inside the AIV as 1100/1200. Of course, I cannot drop the whole AIV into solvent and sonicate it.

Older 1050 AIV do not have the replaceable cartridges, the newer ones do, I get a new AIV. And that's same cartridge as used on 1100.
If your company can't afford that stuff, it's probably cutting corners in other important areas as well.

[Anthony_Ng]

I tried to run Channel B/C/D only and it works! And I flushed the pump with isopropyl alcohol and the dirt washed off. (No need to flush with nitric acid). Now the mobile phase come out as a continuos stream.

Next step troubleshoot is: the degasser

[Consumer Products Guy]

I tried to run Channel B/C/D only and it works!

It works for now; get a new one. If money is that tight, how can your company afford to use the correct type of column, have spare column available, etc. Sorry - can't do this type of work for free.