QPrEST White Papers

Discover the QPrEST standards for absolute protein quantification using mass spectrometry. In our white papers, you can learn more about QPrEST technology and unique features.

Validated Isotope-Labeled Protein Standard for Absolute Quantification Using Mass Spectrometry


  • The QPrEST+ protein standards are readily available and contain peptides validated according to the CPTAC assay criteria
  • The QPrEST+ protein standard provides quantotypic peptides comparable to stable isotope-labeled full-length proteins
  • QPrEST+ shows good linear responses for quantotypic peptides and are suitable for single-point calibration
Using the QTag for LC Retention Time Normalization


  • The QTag present in all QPrEST standards consists of a set of theoretical tryptic peptides which can be used for retention time normalization
  • Retention times of QTag peptides can be accurately predicted using iRT coordinates
QPrEST High Accuracy Targeted Proteomics


  • Stable Isotope-Labeled Protein Standards for absolute quantification using mass spectrometry. 
  • Spiked in early and show a similar digestion efficiency to the endogenous proteins.
  • Used to determine absolute protein amounts in multiple sample types
  • Pre-quantified and ready-to-use

High Accuracy Targeted Proteomics

Learn more about QPrEST standards for targeted proteomics and browse products. 

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