Experimental methods in chemical engineering: Gas chromatography—GC

Abstract Gas chromatography (GC) separates volatile and semi‐volatile liquids and gases based on their affinity for a stationary phase, either a thin liquid or a polymer layer on a solid. A gaseous mobile phase carries the volatile compounds from an injection port to a column with the stationary phase and then to an amdetector. The most common detectors are based on mass spectrometry (MS), thermal conductivity, and flame ionization. A furnace houses the columns and maintains or ramps temperatures to increase the separation efficiency—reduce run time or increase peak separation (resolution). The analyst chooses the chemistry of the stationary phase and the physical structure of the columns based on the polarity and functional groups of the solute. Packed columns tolerate impurities better than capillary columns that have a greater separating power and bleed the functional groups less. Efficiency is best when the sample polarity matches the column polarity. High temperatures and contamination cause columns to bleed the active components, which reduces the resolution but might also introduce ghost peaks to the chromatogram. The Web of Science assigned 15 000 articles to chemical engineering that mention GC and gas chromatography as keywords. Since 2017, it has indexed close to 1000 new articles every year. A bibliometric analysis classifies these contributions into four clusters: (1) pyrolysis and biomass, (2) GC–MS and extraction, (3) lignin and aromatics, and (4) decomposition and kinetics.