Chromatography Forum

I have a 5975 Agilent MS that I believe has been contaminated. What's the best method for a light cleaning short of having Agilent do it? I have heard some people say use Hexane, others say Methylene Chloride, and others say I'm crazy for even trying it. I have another quad assembly I can install if needed, but I would like to try to save this one first.

What I do
take alumina oxide and water to make a paste - scrub each component with a cotton tipped applicator till the dark spots are gone and the metal has a nice shine to it.

soniqate in DI water a few times for about 15-20 minutes each
soniqate in acetone a few times for about 15-20 minutes each
soniqate in MeOH a few times for about 15-20 minutes each

after this wear gloves and place the components back together and back into the MS. Give it some time (half a day to a day) to remove all the air and water while HE is flowing and then tune.


http://www.chem.agilent.com/Library/tec ... 5974EN.pdf

good luck!

Cleaning the quadrupoles is more difficult than the ion source because of the alignment problem. If you dare to take it apart, you can use cotton swab and solvents like IPA, MeOH, Acetone to clean it.

"willnatalie" You are describing ion source cleaning - not quadrupole. Under no circumstances quardupole should be "scrubed"!!!

"MX304" why do You think quadrupole is contaminated? It is quite unlikely unless You analyse some poorly volatile compounds at high GC temperatures or there was some catastrophic malfunction of the vacuum system.

If MS does not tune properly it might be fault of the electrone multiplier or quadrupole needs coils adjustment - "dipping" (we had to do "dipping" recently on 2 years old 5975, the 5971 I had worked earlier needed that after something like 8 years). Quadrupole cleaning is really the last resort and Yes, it can go wrong....

somewhere, I believe the Agilent instructions say something along the lines of "do not under any circumstances disassemble the quadrupole". I've heard that quadrupole alignment is completely critical and incredibly hard to do without the special facilities available at the factory.

I have taken a 5971 that was contaminated from back streaming and held the quads over a beaker and rinsed with solvent (DCM) to clean the rods. It worked - and it only took a week or so to get the DCM signal out of the background.

At the time I was in a group that had about 10 HP MSD's. (HP had not split off Agilent yet.) There was ocasionall discussion of whether to clean the ion burn off of the source end of the quads - and if anyone ever did that, it was with the quads left in the mounting in the instrument - and cleaning with a cotton swab and abrasive. As far as I remember, this was only discussed - primary by a person who had cleaned quads on an older instrument of different manufacture soem time before that.

With the plated, fused quartz quads that came out in the 5972's we knew well enough to leave the quads alone - and they worked well for years. I've not touched an Agilent instrument for several years now, but would give a couple of cautions:

If you remove the quadropoles from the analyzer assembly, you may have an alignment issue in getting them back in, as LMH notes above.

Watch out for the materials used in the assembly. You do not want to melt plastic parts or cause plating to come free from substrate because solvent gets under the plating.

With the advise on using abrasive - only if it is a sold, machined rod - and then it would be good to check with Agilent before proceeding. Service engineers are a great way to learn from other customers mistakes.

Thanks for the responses. The quad was contaminated because of a major vacuum system failure. The check valve on the diffusion pump failed and filled the chamber with oil. I ended up trying my best guess at a solution, and so far it seems to be working. I pulled everything off the analyzer door except for the quad and it's housing. I then flushed it using squirt bottles with Methylene Chloride, then Acetone, and finally Methanol. I dried it with Nitrogen at a very low pressure, and put it all back together.

yea I realized as I now just got back on. My apologies for being trigger happy.

MX304, sounds like a nightmare. The only "good" thing in a situation like that is that you have an instrument so terminally contaminated that you can't make things worse! In a situation like that, the rules on what's OK go out the window... I'm impressed you managed to retrieve a working instrument.

Hi MX304

well done the quad cleaning. I used to do so in the past.
Now the MS chemstation brings the option to bake the quad and the ion source. Many contaminations can be wiped out that way.
Regards