mass spectrometry: chemistry

mass spectrometers consist of what 3 main components?

ionization device → mass analysis → ion detection

hard vs soft ionization

hard ionization if the formation of gas phase ions accompanied by extensive fragmentation of molecules (guy smashes lego car on floor). = more fragments seen

soft is the formation of gas phase ions w/o extensive fragmentation (gently remove each lego piece)= less fragments seen

what kind of ionization is malditof?

soft ionization

what are the 2 classifications of mass analyzers

beam type (magnetic, time of flight): ions make 1 trip thru the instrument and strike the detector

trapping type: ions held in specific regions by combo of magnetic, electric, or electrostatic fields

whats the difference between the 2 beam type mass analysers

magnetic sector= uses magnetic fields

time of flight (TOF) = uses vacuum = lighter ions travel faster than heavy ions

why is a vacuum required in a TOF MS

prevents ions from colliding

GCMS vs LCMS

GCMS is already in the gaseous phase when ingected in to the MS, LCMS the sample is in lighid phase and needs to be converted to the gaseous phase

ion with the highest abundance in a mass spectrum

base peak