What's Inside the GC?1

Let's Open the Door and find out!

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Hmmm…

The column is heart of the GC.

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It is a very, very, long, thin, tube

filled with material called

"packing"

where’s the

column?

The liquid you inject is

heated to a vapor.

The vapor travels through the long, long

tube

When the compound makes it to the end of

the column the detector “sees” it

Which compounds do you think make it through

the column first?

Big compounds or little compounds?

Smelly compounds or not so smelly compounds?

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• Little, smelly compounds

• make it through the column first.

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Volatile organic compounds

The littler and the smellier the compound...

...The easier it is to change the it from liquid to vapor. when you heat it up.

little, smelly compounds are called

volatile organic compounds.

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Here’s a Gas Chromatograph used to determine Blood Alcohol Content

Retention Time is the time that the compound is retained on the column.

Every compound has it own retention time.

You can identify the compound by it’s retention time

You can measure the amount of the compound by the height of the peak.