Page 156 - Basic Gas Chromatography

slightly
few
enthalpy
on
the
indicating
temperature
over
increase
the

oo

in
A decrease
based
in
a
are nearly
are obtained
oo
1/T for
solute
diverge
solute’s
an
prediction

parallel,
and
the
30
of
versus
logarithmically.
compounds
amount
lines
k,
over
that
lines
are
factor,
volume
of
70-50
our
to
constant
9.1
Straight
pairs
relative
proportional
with
retention
Figure
these
retention
many
accordance
decreases
be
the
relationship.
in
for
to
that
100
in
lines
the
assumed
net
is
vaporization
decrease
line
reveals
in
of
solute
the
in
increase
each
log
this
range
approximation,
be
a
150
inspection
the
the
illustrates
of
in
can
of
of
temperature
of
results
slope
an
Lf fects
and
plot
enthalpies
pressure
viz,
time.
00
The
N
vaporization
a
closer
pressure
solutes
phase,
1000
shown.
9.1,
LCINPECIGLUre
first
retention
1.
vapor
limited
Figure
equation
A
the
a
mobile
typical
same.
vapor
range
To
that
the
of
in
a
of (jw) awNjon UORUAIa! 18N other (1) (°K) 1000/T {2}. from permission with Reprinted volume. of retention dependence Temperature 9.1. Fig. & is and Concepts Chromatography: M., J. Miller, From Ltd. Journals, Pergamon 1964, Copyright John of courtesy Reproduced 145. p. 1987, York, New Inc., Sons, & Wil
new
effects
process effective the retention constants 7; tempera- decreases
the very screening general GC, and Clausius—Clapeyron temperature, this
is is It for the in times distribution at temperature
(PTGC) during run. GC a is used often let consider us results. variables important Retention the because the with constant + absolute at pressure vapor (absolute)
Programmed Temperature chromatography gas temperature temperature column and analysis an optimizing detail, in it describing chromatographic gas on EFFECTS two the of one most stationary the of phase. increases temperature as accordance in AH O— At _ RT 2.3 p log of enthalpy vaporization p° and compound’s the is indi
Programmed increasing the for Before temperature TEMPERATURE is Temperature nature the decrease temperature-dependent equation, the is A# constant; gas equation The
9. method samples. of being factors are where the ture.