Question about Shimadzu LCMS-8040 Optimization tool for MRM

[Javier.Ricardo]

Hi all.

I´m working with a Shimadzu LCMS-8040 and I was doing a sensitivity test with reserpine. In the S/N test we inject a 1ng/uL of reserpine.

I set the precursor and the product ion as indicated in the protocol, 609,3>195.0. The signal result was about S:1500 and the S/N:1100.

Then used the optimization tool and the precursor ion was adjusted to 609,8>195.0, run the test but the signal decreases a lot. S:150.

I set the precursor ion back to 609,3 again and run the test. The result was S:2572 and the S/N:1287.

I would like to know if someone has seen this, if it is a particular case with this molecule or if it is some resolution of mass issue due to the tuning file.

[sav]

MRM for reserpine: 609.3 > 195.1 m/z (609.28 > 195.07 m/z)

I think your optimization tool is not working right. Check parameters of optimization tool.

Usually i used auto optimization only at first step (start point) with manual optimization at final step (in most cases i did only manual optimization).