How does gas chromatography testing work?

 After the aromatic compounds (also called essential oils) are carefully distilled from plant material, samples are tested for chemical composition using gas chromatography. In gas chromatography, volatile essential oil compounds are vaporised and passed through a long column called a gas chromatograph. Each individual compound travels or “elutes” through the column at a different rate and is measured as it exits the column during the testing period. Using gas chromatography, quality control engineers can determine which compounds are present in a test sample and, as importantly, at what levels.