Basics of Gas Chromatography

3-5 Cold-on-Column Injection Method

The cold-on-column injection method measures samples that are easily decomposed by heat, have a high-boiling point, or are prone to discoloration. The sample is directly introduced to the column through a cold inlet. The column temperature is then raised for collecting the measurements. Although the entire volume is injected, the solvent enters the cold inlet in liquid form with a very narrow bandwidth. However, when the sample is directly injected into the column, the inlet portion of the column is easily contaminated. The risk of contamination depends on the sample to be measured. Contamination adversely affects the analysis and must be removed by cutting off the column tip. If the frequency of contamination is high, a guard column can be attached and replaced as required.
*Cold-on-column injection can be effectively performed through a special syringe

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