What is the identifier ion and quantifier ion in MS?

Question

What is the identifier ion and quantifier ion in MS? How can i identify the identifier and quantifier ion?

pwd · Answer

Hi, normally we talk about QUANTIFIER and QUALIFIER (identifier) ions in MS. The QUANTIFIER ion is used to quantify your analyte, get a peak area or height after integration of the EIC of the quantifier. This area is used to calculate the concentration after calibration. The QUALIFIER ion is used to identify your analyte, to be sure the measured peak IS your analyte, not matrix or anything else. For this the EIC of the qualifier will be integrated and the area or height will be checked against the quantifier. The ratio of quantifier and qualifier is known and the same without matrix or interferences per analyte. So if the ratio is ok you can be sure your analyte is not affected by anything else. YOU have to choose which ion from your analyte you will set as quantifier or qualifier. Hints: All ions should be higher masses, because they are less affected by matrix. All ions should be specific for your analyte. Check your spectra ions against molecule structure. Check all chosen ions with matrix injection, sometimes the "perfect" quantifier is affected and the "not so perfect" ion are not. BR PWD

What is the identifier ion and quantifier ion in MS?

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