Gas Chromatography Mass Spectrometry (GC-MS) is a specialized analytical technique used in chemistry and forensic science to identify and quantify compounds present in a sample. It involves separating and analyzing individual components of a mixture of chemicals by passing them through a gas chromatograph, and then mass spectrometry is used for identification of the separated chemical components. GC-MS is a highly sensitive and efficient analytical tool that requires specific training and expertise to operate and interpret results accurately.