This is a common follow-up and confirmatory experiment if PMF fails to identify a sample.
This technique is commonly used alongside Pierce's multiplex TMT tags for quantitation. This technique is used after combining the labelled and unlabeled samples together in a SILAC experiment.  John Yates and Jimmy Eng developed the standard software for analyzing the results of this technique using database cross-correlation; that software is SEQUEST. The use of this technique on a drop of blood from a heel prick has replaced the use of Guthrie's test in screening infants for inborn errors of metabolism.  The output of this technique creates b-type or y-type (*) ions. This is a common follow-up and confirmatory experiment if PMF fails to identify a sample. Cleavage in this technique is commonly accomplished using collision-induced dissociation, and this technique is commonly used after cutting a band out of an SDS-PAGE gel followed by trypsin digestion. This technique relies on one analyzer to select a single peptide, which is then fragmented and run through a second analyzer. For 10 points, name this technique from proteomics which essentially uses a pair of mass spectrometers in series.
This technique is commonly used alongside Pierce's multiplex TMT tags for quantitation.
MS/MS or MS2 or Tandem Mass Spectrometry [prompt on “mass spec” or “protein mass spec” or “peptide mass spec” throughout; do NOT accept anything with the word “fingerprinting” in it]