Quantitation/Qualifier Ions

[munkietoes]

Are qualifier ions neccessary for quantitation of known compounds? I have an LC-MS method where I've seperated my two known compounds but when I look at the mass spec, I only have one m/z peak for each chromatographic peak. Is this desireable?

[Ary]

Since you have separated your two compounds and presumably the ions you are seeing in each case are the molecular ions for each compound then yes this is indeed a desirable scenario. By having just one ion you are maximising your signal to noise ratio.

[Mary Carson]

You may not need qualifier ions for known compounds where you KNOW the compound is in the sample (e.g., PK studies). However, if you are doing contaminant analysis where you are trying to establish that your known compound is in an unknown sample, you probably need some qualifying ions.

[munkietoes]

Thank you very much for your input!