Tuning of a compound in MS/MS

[prashantnaik07]

Hi

What is the general procedure for tuning a compound of unknown mass
in MS/MS? can anyone pls explain this to me in a detail manner.

Thanx in advance

Prashant

[Kostas Petritis]

Why do you want to tune for? MRM experiments or in order to achieve the most informative MS/MS spectra? Briefly, you would do a full scan to identify the mass of your compound, isolate and then fragment by ramping the collision energy... Depending on what you want to do then there are different paths you want to take...

[prashantnaik07]

Ok after doin the full scan i will come to know about the mass of the parent ion, but if i want to quantify that parent ion and its fragments then do i have to fine tune the parameters like DP,FP,EP and CE again . can you please give me the general sequence which i should follow if i want to quantify the compound of unknown mass.

Thanx

[Kostas Petritis]

Some of these parameters will affect the intensity of the parent ion and some of them the intensity of the daughter ion(s) (you should be able to say which one is which). From the abreviations you gave I guess you work with a Sciex triple quadrupole mass spectrometer... You want to optimize all the voltages individually and then perform SRM or MRM experiments by selecting the highest intensity daughter ions in order to quantify your compound (although I do not see how you are going to do it if your compound is unknown and you do not have a standard, unless you will try to identify by MS/MS and then buy the standard and do the quantitation)...