Mass axis off for ion 502 - Agilent 5975c

[tulsachemist]

I can't seem to get the mass axis correct for 502. Every tune I do ends up at 501.9. I tried swapping out the source but still get 501.9. Has anybody else seen this problem?

[AICMM]

That is 502. If I recall correctly, the spec was +/- 0.1 but it has been a while. 502 is not that strong an ion anyway so you might be faced with too little signal as well but essentially you are there.

Best regards,

AICMM

[James_Ball]

The autotune functions will usually end once it is within +/- 0.1 of the target. If you really need it to be 502.0 you may have to tweak the Mass Gain and Mass Offset numbers manually. Another thing you may notice is that the mass axis will be slightly different between Scan and Profile in tune.

Put in into Manual tune and Profile mode and adjust the Mass Gain and Mass Offset numbers one click at a time both positive and negative until you get a feel as to how they affect the numbers then just tweak the settings until you get the desired results. Gain will affect the higher masses more than lower while Offset affects them all equally I believe(but that may be reversed).

AMUGain and AMUOffset are used to adjust your peak widths in the same manner.