Page 173 - Basic Gas Chromatography
P. 173

1?   size,   systems.   was   it,   to   species   and   top   sequen-   through   rapid   from   or   and   Figure   and   differ-   larger   until   essential   other   function   the

          small   compared   which   quadrupole   applied   charged   top   the   the   enters   trajectories   eject   them   of  capable   differ   dissociation   continuous   a   ions   the   in   surface   potential   a  where   times   1-million-fold.   an   is   with   a   as   and

          simplicity,   GC—MS   for   resolution  when   analyzer   the   of   frequency   for   on   caps   GC   stable   in   to   altered   pass   and   often   undergo   usually   count   schematically   a   by   surface   several   about   This   collision   abundance   abundance




          of   ideal   it   mass   version   region   end   two   the   from   trapped   and   trap   cost,   in   generated   may   detector,   to   used   shown   semi-conductive   accelerated   repeated   magnified   vacuum.   by   species   ion   ion   of   ELECTRON   CURRENT   IONS   CAP   END   analyzer.
          advantages   make   low   has   trap   ion   simpler   a   radio   a   stable   a   are   Effluent   then   frequency  can  be   ion   the   modest   spectra   ions   trap.   a   is   is   the   are   semi-conductive   is   is   high   under   charged   the   of   ratios   the   FILAMENT   mass





          the   which   and   an   is   It   only   define   There   and   from   design,   The   some   ion   produced,   multiplier,   detector   strike   These   process   input   is   the   plot   a   NOE   ®   eee   %6)   —\\   trap   Ion
          has   scanning   Daltons   spectrometers.   schematically   GC-MS.   having   to   space.   electrode.   ionized   radio   ratios   in   applications.   and   the   ions   Such  a   analyzer   the   of   This   weak   system   of   simply   conditions,   CAP   10.7.
          analyzer   rapid   2,000   about   mass   for   electrode,   monopole   a   electrode   ring   are  analytes   The   m/z  selected   detector.   simple   spectra,   inside   the   of   electron   an   spectrum.   mass   electrons.   of   portion   results.   original   MS   entire   loss   the   avoid   surfaces.   is   controlled   END   RING   ELECTRODE   ELECTRON   MULTIPLIER   Fig.



          quadrupole   and   cost,   to   focusing   shows   10.7   specifically   ring   the   as  essentially   circular   circular   the   of   some   ring  electrode.   with   the   to   cap   also   are   traps   GC-MS   for   quadrupole   collisions   separation   of  version   mass   a   the   from   cascade   another   electrons   of   the   of   the   that   to   or  molecules,   spectrum   mass   Under   RF




    GC-MS   The   moderate   restricted   is   It   double   to   Figure   developed   which   in   serves   the   inside   bottom   cap;   end   the   inside   ions   tially   end   the   Ion   scanning   classical   ion/molecule   After   dynode   generate   Ions   10.8.   a  release   to   ence   cascade   amplification   Note   requirement   ions,   The   m/z.   of







    Topics                                            ME            i   reach   annihi-



   Special   i                                    240   il   T   250   240).   Dependin  current potentials   and   be   Detector   7


                                                           =        rods.   rods   and
                                                    4—1   T   200   (MW   four   the   rods
                                                           ortal   the   direct   through   the
                                        156                of      to   the   strike                       Quadrupole   analyzer.

                                                      150          pplied   will                              mass
                                                   rT      spectra    and   pass
                                        140        tnm—te   El   and   appli   frequency   will   ratios

                                                          CI       also   ratio                               Quadrupole
                                                   {   100   of    is     m/z
                                        I.                           radio
                                        E.                Comparison   frequency   of  the   mass-to-charge   other   Fig.   10.6.


                                                     50
                                                   T                      with
                                                          10.5.    radio   one   Ions
                                                          Fig.     A  Tadi   combination
         100                                    20   0                 only   detector.                    ,
  158   JONVONNAY  SALLY 1aY¥     JONVONNEY  SAILV14u              reversed.   the   on   of   ions   ine   ated.   Source
   168   169   170   171   172   173   174   175   176   177   178