GC-MS laboratory of the Department of Veterinary Pharmacology and Toxicology is equipped with Agilent Model 7890 A GC-MS system. Gas Chromatography-Mass Spectrometry (GC-MS) is a combination of two techniques to identify the volatile fractions with low detection limits. The setup is configured with NIST library possessing over lakh of compounds encompasses database of volatile substances, pesticides and other environmental pollutants. GC-MS technique is a well known analytical tool to determine the volatile substances from the group of similar type of entities. It is a hyphenated and sophisticated tool that amalgamates the GC separation with the highly sensitive detector in the form of mass spectrometer. The samples injected gets ionized and accelerated by the quadrupole assembly and thus gaining different trajectories owing to their mass to charge ratios until they settle down.