Gas Chromatography

GC - Instrumental componentsSample injection portFor optimum column efficiency, the sample should not be too large, andshould be introduced onto the column as a "plug" of vapor - slowinjection of large samples causes band broadening and loss ofresolution.The most common injection method is where a micro syringe is used toinject sample through a rubber septum into a flash vaporizer port at thehead of the column.The temperature of the sample port is usually about 50°C higher thanthe boiling point of the least volatile component of the sample.For packed columns, sample size ranges from tenths of a micro liter upto 20 micro liters.