. 2021 Jun 6;42(2):546–576. doi: 10.1002/mas.21709

Table 1.

Classification of chemical isotope labeling approaches based on different criteria

	MS1quantification	MS2quantification	Isotopiclabeling	Isobariclabeling	Ultra‐high resolution at MS1	Ultra‐high resolution at MS2
(c)ICAT	√		√
Dimethylation	√		√
ICPL	√		√
mTRAQ	√		√
mTMT	√		√
DiPyrO	√		√		√
mdDiLeu	√		√		√
iTRAQ^a		√		√
TMT		√		√		√
DiLeu^a		√		√
IBT		√		√		√
DiART		√		√		√
IPTL		√		√		√
m‐pIDL		√	√			√
Ac‐IPG		√		√
TMTc(+)		√		√
EASI		√		√
Ac‐AG		√		√

^{^a}

Although the iTRAQ and DiLeu series labels have mDa differences in precursor masses, they are classified as isobaric since the mDa differences are not revealed at the MS1 level in general use and they are already habitually referred to as isobaric.