Analysis of Mexican reference standards for Bursera spp. resins by Gas Chromatography-Mass Spectrometry and application to archaeological objects

Copal samples from two Aztec objects belonging to a collection of offerings found at Templo Mayor site were analyzed by GC-MS The first sample was part of an adhesive material found in the base of a ceremonial knife; the second sample comes from an amorphous artifact probably offered as spiritual material. In order to determine their botanical origin, resin samples from eight certified botanical species from Mexican Bursera were studied. The chromatographic study of their triterpenic composition allowed to establish a botanical origin related either to Bursera bipinnata or Bursera stenophylla species which triterpenic composition is identical. It is the first time that GC-MS analyzes were performed on samples from certified botanical origin of Mexican Bursera resins which aimed at getting an overview of the molecular composition and variability of copal resins and at establishing an analytical tool to characterize the botanical origin of archaeological samples.