In-tube dynamic extraction a green solventless alternative for a sensitive headspace analysis of volatile organic compounds in olive oils

To analyze the volatile organic compounds of olive oils, an automated, robust and sensitive and solventless in-tube extraction dynamic headspace (ITEX-DHS) GC-MS method was developed, optimized and validated. 21 VOCs, typically appearing in olive oils and extra virgin olive oils, were used to develop the method. The extraction procedure was optimized for incubation time, incubation temperature, number of extraction cycles and desorption volume. Repeatability was between 1 and 9% for all analytes, except octanal (11%), and a good recovery (84- 118%) was found. The ITEX-DHS method allowed VOC analysis in olive oils at much smaller concentration than in previous studies using solid phase microextraction, with limits of detections from 0.1 to 68.6 mu g kg-1. In terms of an application, a linear discriminant analysis (LDA) was conducted including 31 olive oil samples from five different geographical origins, which led to 90.3% correct predictions.