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Hello to everybody. It's
a pleasure for me to
be here today to talk
about gas chromatography,
and I'll be giving
you a brief overview
and some information
on recent advances.
As you can see here,
my name is Peter,
and I work in Messina, Sicily.
I'm a professor in food chemistry
and, more specifically,
I work with gas chromatography
mainly in the field
of food chemistry.
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So, gas chromatography,
what is it?
For me, it's a simple
science, and that's
probably why I like it so
much, but also fascinating.
Why is it simple?
Because basically,
we have a flow of gas
inside a rather long tube
containing a mixture
of different analytes.
These analytes are when
we introduce a sample
at the entrance of the
column, they're all together,
and ideally they become
separated when they reach
the end of the column.
This is obviously
not always the case.
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Now, what is it used for?
It's used for the
separation/analysis
of volatile or
semi-volatile compounds.
Now, what does that mean?
I would say anything up
to around 600 daltons,
thermally stable, not always,
because we do inject
our sample into
what is a hot injector with
temperatures up to 350°C,
and so, many times some analytes
will undergo different
degrees of degradation.
What columns are used?
There are different
columns available.
We have packed
columns, for example,
we have porous-layer
open tubular columns,
but the most common by far are
fused-silica open tubular
capillary columns.
Now, in gas chromatography,
all separations are
tightly related to
vapor pressures or boiling
points but also to polarity.
Therefore, interactions
with a stationary phase
which is located on
the inner surface
of the fused-silica
capillary column.
Now, gas chromatography
methods can be either
or we can subdivide them into
one or multidimensional.
A one-dimensional GC method
basically uses a single column.
A multidimensional GC method
which are mainly
two-dimensional.
We rarely get over
two dimensions;
sometimes, very rarely, three.
A two-dimensional GC method
uses two GC columns.
