Chromatography Forum

Hi.
First, I'm sorry for my bad english. I hope that you understand me.

I work a MSD 5973.
Two weeks ago, I noticed that the chromatograms was flat.
Then, I executed the autotune, but this did not finish.
I cleaned the ion source and the HED, but nothing changed.
After that, I removed the column and placed a new column.
In this moment, I can execute the autotune, but the results are not good:

EMVolts: 2906
#peaks: 437
Mass 69 precursor: 10.42
Mass 219 precursor: 52.08
Mass 502 precursor: 51.23
Position of isotope mass 70: low
Position of isotope mass 220: low
Ratios of isotope masses: horrible

Can somebody help me?

Astroguille,

Wid219 is the width of the 219 ion. Since it is in the middle of the PFTBA tune and a strong responder, adjusting the width of that ion really can affect the outcome of the tune.

Cleaning the source was a good idea. Cleaning the HID was probably not. I would start by replacing your HED and re-running an autotune. Then post the autotune and there are a number of people who can help you resolve what ever issues remain. With the number of peaks detected, I think you are only looking at noise because the HED may be fried.

By the way, it could have been as simple as changing from filament 1 to filament 2.

Best regards.

The EM voltage is very high. How old is the electron multiplier? It could be at the end of its useful life.

Your EM voltage is very high....habitually, you need to change your EM at this moment but beforee change your EM, verify:
1-If your calibration vial is not empty
2-If you select the good tune mode.
3-If you have not a leak with ion gauge.
4-Disconnect your column and cap your ms interface, it is more easy to diagnostic a problem with this manner...tune again with no column
5-Change your EM