Page 35 - Basic Gas Chromatography
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21                    in   a   as   of   36   so   the   are   of   size   not   and   even   badly   phase   all   (liquid)
                             but   it   narrow   microliter   wL   be   column   of   types   smallest   sample   will   work,   sizes   be   possible   gas   special   convert   liquids.   ul   pl*   ul*
                             column,   introduce   and   1.0   600   to   mL/min),   1   would   poor   part   guidelines   three   the   the   components   trace   may   it   the   pose   to   to   Sizes  Sample   0.2-20   0.01-2   0.01-3

                 Column      the   onto   to   is   sharp  sample   a   of   vaporizes   of   rate   This   very  produce   important   critical.   is   general   for   sizes   resolution,   larger   For   sample   large   peaks   making   in   be   liquids   heated,   components   techniques.



                 Capillary   Split   Splitless   On-column   goal   the   vaporization   benzene   flow   a   column.   the   and   very   a   sample   Some   sample   maximum   the  sample,   other   of   solute.   use   to   major   The   larger,   be   sample   and   gases   be   all   Types   splitting


             INLETS          instantaneously   realistic   difficulty  keeping   the   the   (at  column   onto   it   result   is  sampling   the   of   size.   typical   and   used.   be   the   presence   given   a   of   best   column.   will   peaks   entire   the   of   either  should   convert   to   possible.   Column         film      sample   by


       Devices   SAMPLE      injected   more   a   and   considering   injection,   capillary   carry   to   would   band   size   the   and   sample   lists   2.1   shape   always   in  present   the  cases,   shape   often   is   it   the   (trace)   that  require   Mixtures   mixtures   pressurized,   always   Different   liquid   10%   liquid   wm   0.2   i.d.,   obtained


       Sampling   Column   vaporizer   is   impossible   The   band.   by   Upon   a   of   required   broad   Clearly,   N).   process   optimum   Table   peak   best   should   components   most   peak   and   work,   “overload”   desired   results.   use.   in   or   not   is   for  Volumes   0.d.,   4”   3%   0.d.,   3”   wm   250   often   are



       and       Packed   Flash   On-column   sample   is   appreciated   benzene.   case   be   initial   (low   single   no   however.   the   size   In   be.   location   will   the   desired   methods   conditions   possible,   gases,   to   this   Sample   packed:   packed:   tubular):   sizes
       Inlets                the   this   symmetrical   of   the   In   would   an   that   chromatographic   is   For   sample   more   to   need   the   preparative-scale   they   but   the   Sampling   sampling   the   If   Unfortunately,   2.1   Types   analytical   efficiency   (open   sample


       Sample                Ideally,   practice   sharp   be   can   sample   vapor.   seconds   slow   performance   There   available,   columns.   possible   The   may   affect   for   though   distorted,   achieve   to   Gas   Gas   under   problems.   components   TABLE   Column   Regular   High   Capillary   These   *









       Overview   of   area   and   the   is   p;,   com  Pressed   volumetric   at   is   it   must   be   (2)   (3)   av   4 the  called   the   (4)   volume   to   gases,   intro-   intro   different



      Instrument   cross-sectional   pressure   inlet  pressure,   is   gas   e   the   to  outlet.   the   outlet  where   flow  outlet   time,   the   volume   is   retention   including   quantitatively  vely   require





             the        under   the   the   column;   column   the   at   the   j:   VII.   retention     samples   and   ,   types   list:
             by         is   pressure,   Co  nsequently,   the   the   F,,   factor,   A ppendix   a   rete ntion   adjusted   DEVIC ES   o f   c  olumn   fo lowing
             multipl ying   IV.   colu mn   GC   thro  ugh   head   of   meas ured   is   ra te,  flow   =]   X F,   the   fro m   resulting   =j te F.   with   the   variety   r.  apidly   be   Different   the




             by     Gas   a   atmospheric   pressure,   po.   passes   it   the   rate   flow   average   compressibility   F.   in  given   volume   the   V2:   7 Ve   =   confused   SAMPLING   wide   a   them   to   in
            achieved   Appendix   Carrier   entering   at   as   from   the   so-called   are   retention   and   volume,   VR   be   chapter.   handle   permit   stream.   indicated



            is   See   of   the   gas   usually   outlet   expands   increases   volumetric   get   of  j   a   used,   be   not   next   AND   should   and   :   gas   as  inlets
            mL/min)   (mr?).   carrier   is  outlet   than   the   and   also   the   To   the   by   values   calculates   should   retention   should   the   in   INLETS   inlet   solids,   the  carrier



            (in   column   Compressibility   the   greater  :  inlet   the   rate   Usually   maximum.   multiplied   typical   one   rate   term   presented   sample   and   sample   of

     20     rate   the   Since   column   at   flow   a    and:        Some   If   flow   corrected   This   be   SAMPLE   The   liquids,  :  into   duced   types
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