TKO6: A Peptide Standard to Assess Interference for Unit-Resolved Isobaric Labeling Platforms

摘要

Protein abundance profiling using isobaric labeling is a well-established quantitative mass spectrometry technique. However, ratio distortion resulting from co-isolated and co-fragmented ions - commonly referred to as interference - remains a drawback of this technique. Tribrid mass spectrometers, such as the Orbitrap Fusion and the Orbitrap Fusion Lumos with a triple mass analyzer configuration, facilitate methods (namely SPS-MS3) that can help alleviate interference. However, few standards are available to measure interference and thereby aid in method development. Here we introduce the TKO6 standard that assesses ion interference and is designed specifically for data acquired at low (unit) mass resolution. We use TKO6 to compare interference in MS2 versus MS3-based quantitation methods, data acquisition methods of different lengths, and ion trap-based TMT reporter ion analysis (IT-MS3) with conventional Orbitrap-based analysis (OT-MS3). We show that the TKO6 standard is a valuable tool for assessing quantification accuracy in isobaric tag-based analyses.