The column is heart of the GC. 4 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? 6
Little, smelly compounds make it through the column first. 7
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. 8
9 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.