Chromatography Forum

I am running an Agilent 1100 LC/MS with an Edwards single Turbopump (ceramic bearings, I think) and an Edwards 18 mechanical pump. Less than 2 months ago, the turbo pump was replaced due to a failure. The new one is an Edwards rebuilt one. Before the turbo was replaced, I also changed the mechanical pump oil. Now after less than 2 months having it running - basically less than a handful of samples run - it looks like I might be having some power supply problems preventing operation, but it might also be a function of insufficient vacuum. I just changed the mechanical pump oil today and its completely loaded with very very fine black particles - enough to make the fluid look virtually black when disturbed.

I have never seen anything like this on any Mass spec or vacuum system I have worked on. I did swipe the intake metal hose just above the entrance to the mechanical pump with a gloved finger and found some black particles there too;there didn't seem to be any oil associated with them, ie very dry, so I don't think it was "kicked up" by the mechanical pump. I'm almost dreading the idea that it might be coming form the MSD of the LC-MS.

Has anyone seen this before? Any suggestions?

Thanks.

Oldspecguy

Oldspecguy,

Do you know if these particles are organic or inorganic? (via IR or EDS?)

Do you use ''exotic'' solvents on your LC-MS?

Best wishes,

bhuvfe

Don't know if it is inorganic or organic BUT I do know that it is coming from the MSD. I found the same type of "soot" in the flexible metal hose just downstream of the analyzer/turbo area. It looks like it is from either the "new" rebuilt turbo or remnants of the old failed one.

Primarily using Hexane with varying amounts of DCM (primarily 2-50%) - nothing exotic here. I am beginning to think it was something not done properly with the rebuilt turbo.

Agilent will be coming in the next week or so.

Thanks