Targeted metabolomics is quantitative and derives its information from discovery experiments, literature and/or clinical observations before a model or hypothesis is tested.
Testing involves verification and validation of defined groups of known metabolites across large sample sets. These experiments require accuracy, high throughput and reliability. For large scale targeted profiling, using a high resolution accurate mass (HRAM) workflow is optimal, while for routine quantitation, selected reaction monitoring (SRM) on a triple quadrupole MS is the preferred solution.
In the targeted metabolomics workflow, analytical or technical reproducibility is key to experimental success. High analytical reproducibility means that findings are due to actual biological variance. It also minimizes experimental replicates, so a smaller number of samples need to be analyzed.
Large scale targeted profiling offers a new perspective on targeted quantitation when compared against the gold standard of quantitation using SRM and triple quadrupole MS. Using HRAM mass spectrometry, targeted analysis can be performed using a method called parallel reaction monitoring (PRM) . This method offers greater selectivity, confirmation of data with MS/MS and retroactive data analysis. There is also less method development.
There are three steps in a targeted profiling workflow:
For routine quantitation of well characterized metabolites, SRM using triple quadrupole MS is the gold standard. The advantages of this workflow include reduced interference, increased detection sensitivity, and streamlined method creation and data acquisition. SRM transitions that are developed from targeted metabolites generate the best signals.
There are three steps in a routine targeted quantitation workflow: