abstract |
A method of mass spectrometry (MS) quantification of an analyte, comprising preparing a heavy, isotopically-labeled sequence or portion thereof which, upon MS dissociation, fragments into a predictable series of ions from a sample with an analyte, wherein the analyte has a known, defined sequence for specifically identifying and quantifying the analyte, wherein the sequence is cleavably linked to a reporter sequence R; providing a heavy, isotopically labeled universal reporter U having a sequence which is identical to the sequence of the reporter R but independent of the sequence of the analyte cleaving, and quantifying the universal report U to quantify the reporter R which is in equimolar concentration as the heavy, isotopically labeled analyte, determining the amount of analyte in the sample. |