Thymol and carvacrol determination in a swine feed organic matrix using Headspace SPME-GC-MS

In recent years, oregano essential oil has been used as an animal food additive due to its antifungal and antibacterial properties as well as s synthetic antibiotic substitute. It is desirable to develop fast and effective thymol and carvacrol quantification method in a swine feed organic matrix. In this work, a performance comparison between the Soxhlet solvent extraction technique using petroleum ether and ethyl acetate and the head space-solid phase microextraction (HS-SPME) technique is made. A 2(4) design of experiments is performed for defining HS-SPME parameters: equilibrium temperature of 40 degrees C, extraction temperature of 40 degrees C, ionic strength of 0.57 M, and extraction time of 40 min. The HS-SPME method is more efficient for extracting thymol and carvacrol extraction from an organic matrix. Limits of detection and quantification values using Soxhlet extraction with ethyl acetate were 3.7 and 12.5 mu L-1 for thymol and 1.4 and 4.7 mu g L-1 for carvacrol, respectively; while LOD and LOQ for HS-SPME were 0.9 and 3.1 mu g L-1 for thymol and 0.6 and 1.9 mu g L-1 for carvacrol,respectively. The head space-solid phase microextraction method has the potential for quality control in the industry for active compounds present in oregano's essential oil as an additive into an organic matrix.