Poor sensitivity with MSD5977A AGILENT

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

5 posts Page 1 of 1
Hi,

I have a problem with one of my MSD5977A of AGILENT.
At the beginning I had decreasing in general sensitivity and was decreasing week after week until I cannot use it anymore. I Vented the MSD and cleaned all the source (Like I always do with my other MSD : Alumina powder and subsequent sonicing bath with solvents) but the sensitivity was still bad.

I decided to run a Ramp lenses and the emission ramp was curious. I had never seen that before, The emission show one pic for 69 and then goes crazy for 219 and 502 sometimes it got a topped line, after that no emission showed and sometimes it goes up and down. I contacted AGILENT and they told me to replace the source. It's expansive and I managed to change almost all of it, except the repeller assembly (the heater block only) and the body.

Still have the same issue. I want to know before ordering the remaining parts if that could be an electronic problem?
And do I focus too much on that, since the new repeller still topped.

Thank you for your help,
Hi,
For more information, the Emission ramp for ion 69 show half a normal emission with a peak at 34.6 going from 0 to good intensity but for 219 and 502 I got only a min max at the same intensity, around 43.

I will try to vent another MSD with same model to swap source.

Thank you,
I never ramp the emission when testing a source. A setting of between 15 and 45 uA is where it should normally be. Ramping it up to very high levels puts too much energy into the source and gives very bad results, and too low and you don't get fragmentation.

I think the default is 35 uA on the newer sources.

Set it to 35 and then ramp the other lenses and see what results you have.

Do you have the Extractor source or a normal source, or possibly the new high sensitivity source?
The past is there to guide us into the future, not to dwell in.
Hi,
I have the EI 350 source and I was able to switch another EI 350 source from another 5977A MSD and it does the same for the MSD I am speaking of, but was working great for the other MSD. It is more like an electronic problem from the ceramic or board or the door board. Next thing to test.

Note : I am currently using 34.6µA once the MSD is back on track I can try to adjust it to 35 µA.

Thank you,
Simon C wrote:
Hi,
I have the EI 350 source and I was able to switch another EI 350 source from another 5977A MSD and it does the same for the MSD I am speaking of, but was working great for the other MSD. It is more like an electronic problem from the ceramic or board or the door board. Next thing to test.

Note : I am currently using 34.6µA once the MSD is back on track I can try to adjust it to 35 µA.

Thank you,


On my 7000 I did have to replace the filament control board on the outside not long after we got the instrument. Easy to replace, it is the smaller one on the outside where the pins pass through the side plate. The source and boards are similar on the 5977 I believe.
The past is there to guide us into the future, not to dwell in.
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