GLC is the abbreviation for gas liquid chromatography, the classic technique in which volatile food components separate as they partition between a carrier gas and a liquid stationary phase. The shorthand appears in older literature and methods for fatty acid, flavour and residue analysis, where GLC with flame ionisation detection was long the standard quantitative approach. Modern capillary GC has largely replaced packed-column GLC, but the abbreviation persists in method names and historical data. Analysts reading vintage specifications should recognise GLC as the same fundamental technique as today’s gas chromatography.