between ion desorption and acceleration into the flight-tube of a MALDI-TOF mass spect media. ... Coupling of MALDI to tandem mass spectrometers such as quadrupole-TOF (MALDI q-TOF), TOF-TOF (MALDI-TOF-TOF ... The phosphoamino acid content ratio (pSer:pThr:pTyr) of a vertebrate cell is 1800:200:1.