Absolute quantification of toxicological biomarkers by multiple reaction monitoring

With the advent of “–omics” technologies, there has been an explosion of data generation in the field of toxicology, as well as in many others. As new candidate biomarkers of toxicity are being regularly discovered, the next challenge is to validate these observations in a targeted manner. Traditionally, these validation experiments have been conducted using antibody-based technologies such as Western blotting, ELISA, and immunohistochemistry. However, this often produces a significant bottleneck as the time, cost, and development of successful antibodies are often far outpaced by the generation of targets of interest. In response to this, recently there have been several developments in the use of triple quadrupole (QQQ) mass spectrometry (MS) as a platform to provide quantification of proteins by multiple reaction monitoring (MRM). This technology does not require antibodies; it is typically less expensive and quicker to develop, and has the opportunity for more accessible multiplexing. The speed of these experiments combined with their flexibility and ability to multiplex assays makes the technique a valuable strategy to validate biomarker discovery.