Presented by Christa Cobbaert, Leiden University Medical Centre, Department of Clinical Chemistry and Laboratory Medicine, Leiden, the Netherlands.

Tandem mass spectrometry (MS) is advertised as a detection and quantification method that alleviates most of the flaws inherent to immunoassays. In 2012, MS-based targeted proteomics was declared method of the year as it allows quantification of either specific proteoforms* or specific subsets of proteins of interest. MS-based targeted proteomics can also be used in a highly multiplexed format and allows for precise molecular characterization of the measurands. Targeted proteomics is frequently performed using a typical MRM-workflow consisting of five steps: defining the protein set of interest based on the clinical or biological question; selecting appropriate peptides which are proteotypic and have suitable LC/MS properties; selecting transitions based on their intensity; analytically validating the transitions to prevent interferences and quantitating the specific protein(s) by calibration using either value-assigned peptide or matrix-based calibrators.

For Research Use Only. Not for use in diagnostic procedures.

Agilent recommends the 6495C Triple Quadrupole LC/MS for peptide quantitation research.