Rapid GC/MS test for identification of Olea europaea L. leaves in ground oregano

Various ethanol extracts of dried oregano samples purchased from international wholesale traders and from retail markets have been examined by GC/MS: the same procedure was conducted with various samples of olive leaves. The extracts were studied in the chromatographic region where the volatile compounds of high mass can be eluted. The experiments revealed that two markers derived only from olive leaves were identifiable in oregano extracts containing olive leaves, also at very low levels. This paper describes the operating conditions useful to realize the test which permits to evidence the adulteration of commercial batches of ground oregano containing olive leaves added as bulking agents.