Vapor Pressure Measurements on Linalool Using a Rapid and Inexpensive Method Suitable for Cannabis-Associated Terpenes

Abstract

Vapor pressure (p sat) data are needed to assess the potential use of terpenes as breath markers of recent cannabis use. Herein, a recently introduced gas-saturation method for p sat measurements, known as dynamic vapor microextraction (DVME), was used to measure p sat for the terpene (±)-3,7-dimethylocta-1,6-dien-3-ol, commonly known as linalool. The DVME apparatus utilizes inexpensive and commercially available components, a low internal volume, and helium carrier gas to minimize nonideal mixture behavior. In the temperature range from 314 to 354 K, DVME-based measurements of the p sat of linalool ranged from 81 to 1250 Pa. With a measurement period of 30 min, the combined standard uncertainty of these measurements ranged from 0.0358·p sat to 0.0584·p sat depending on temperature. The DVME-based measurements agree with a Wagner correlation of the available literature data. We demonstrate that DVME produces accurate results for values of p sat that are 200 times higher than in the DVME validation study with n-eicosane (C20H42). The oxidative stability of linalool was improved by the addition of 0.2 mass % of the antioxidant tert-butylhydroquinone.