Page 175 - Basic Gas Chromatography
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resolving   provides   ppb   complicated   operators.   of  systems   professors.   GC-MS   Note   times   system.   generating   of   =   m/z

   161            level.   and   $40K             the   This   per   n-   of   An   and   71, 57,   57,


             high   MS   the   systems,   from   lack   on   run   10.9).   half height.   10   fragmentation   and   however,   m/z   1.50
             the   the   while   to   down   cost   low   range   more   are   GC-MS   a   both   college   sample   Fig.   at   about   GC-MS   electron   stable,   case   abundance,   2-Methylbutane   Pentane   Cyclopentane   Hexane   Benzene   >   hydrocarbon mixture.
             techniques:   retained,   analyses   for   Costs  systems.   they   item;   skilled   of   to   due   many   of   hydrocarbon   (see   FID   less   or   peak   GC   the   for   an   of   one   not   is   this   in   highest   1.   2.   3.   4.   5.   (min)   a   of





             both   is   common    lack   systems   expertise   an   with   second   1   the   spectrum.   mechanism   source   ejecting   species   fragments;   the   1.00   (TIC)
             of   GC   of   quantitative   are   expensive   systems.   expense   a   is   GC-MS   of   a   of   would   around   scan   mass   ion   the   This   stable   with   chromatogram
             advantages   analysis   and   Daltons   more   bench-top   Systems   capital   a   there   and   on   lack   the   chromatogram   it   as   typically   must  system   good   proposed   in   10.9)   molecule,   86).   =   more   fragment       TIME   ion




          GC-MS   the   of   speed   identification   600   to   10   for   simple   GC-MS   are   GC,   a   students   and  purposes   appearance   widths,   MS   a   get   to   a   shows   Fig.   in   parent   the   (m/z   ion   to   That   0.50   Total


          of   ombines   the   of  ranges   Daltons   for   of   instruments   than   train   Analysis   capillary   same   peak   the   that   order   10.10   4   (peak   strikes   molecular   decomposes   Daltons.   29   RESP.      10.9.   Fig.


    GC-MS   Capabilities   -   and   ower   positive   both   Mass   1000   to   up   $75K   to   up   Limitations   GC-MS   operate   to   colleges   Few   teaching   for   Data   typical   A   the   has   narrow   means   in  second   Figure   hexane   electron   the   rapidly   and   43








   Topics                              can   be   of   isotopes   tool.   It   as   well   was   It   probably   introduced   instruments   instru-   not   mass   would   market   as   systems   Daltons;   resolution   tough   40-400   instruments


   Special                             They   structure   atomic   analytical   as   and   considerable   sector   could   generate   a   analyzers   information   requirements   600   The   quadrupole,
          Surface   lons   of   version).   compound.   chemical   separate   an   compounds,   compounds,   products   been   not   early   The   requiring   Magnetic   however,   they   to   scanning   analytical   huge   much   ““GC-MS”   GC.   MS   the   about   to   high  possessed   “pure”’.   be   (hopefully   rugged   The



         Semi-Conductive   ascade   Detector   (continuous-dynode   each   for   the   and   to  spectrometer   improved   as   unknown   organic   and   petroleum   GC   if   had   Gohlke   [6].   usually   running.   analyzer;   necessary   Faster   was   GC   a   as  provided   the  dedicated   the   for  detector   would   GC,   a   be   limited   be   GC   the   most   cases   devices  scanning   more  simple,   laboratories.   need.






                               multiplier   unique   are   weight   mass   and   identifying   inorganic   of   dramatically   by   1959   in   complex,   and   them   keep   of   type   seconds)   (few   from   GC.   a   that  obvious   detector   born   was   a   as   inlet   could   range   because   in  would   rapid   and  second)   analytical   this   met



                               Electron   present   molecular   a   used   developed   for   of   both   characterization   more   GC   to   cumbersome   to   popular   scanning   eluting   was   GC   no   but   Thus   designed   sample   the   mass   satisfactory   peaks   of   per   routine   in   designs,


                               10.8.     the           slowly   powerful   structures   the   even   coupled   maintenance   most   peak   it   1960s,   MS.   was   that   The   eluting   development   times   used   trap

                               Fig.    species   establish   Thompson   was   be   for   grown   first   the   rapid   a   rapidly,   from   MS   simplified.   was   the   so   be   ion
                                       m/z   compound.   J.   MS   to   used   have   was   expensive,   and   were   the   of   required.   late   the   growing   available   new   a   specifying   resolution   the   several   could   the
                                       specific   to   History   J.   1913,   proved   elucidating   1952.   MS   expertise   provide   spectrum   By   By   be   capabilities   was   Daltons   later,
    160                                  used   each   After   in   widely   would   in   were   ments   be   and   was   where   could   low   part   which   and
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