Evaluation of 3,5-stigmastadiene content of edible oils: Comparison between the traditional capillary gas chromatographic method and the on-line high performance liquid chromatography-capillary gas chromatographic analysis

Summary The quantitation of 3,5-stigmastadiene and other steroidal hydrocarbons, commonly known as steradienes, is a valid tool for the recognition of refining (in particular bleaching) of edible oils; the evidence of this process is nowadays of a great interest due to growing market for virgin, cold-pressed, natural oils. Due to the long time required (about 4 hours) and the amount of solvents employed (about 650 mL) to perform the official analysis, other methods have been recently proposed, the most important of which involves high performance liquid chromatography coupled with capillary gas chromatography (HPLC-GC). In this study the results of ten oil samples, analysed by both the official method and HPLC-GC, are reported and the two methods compared and discussed, for routine use, in terms of sample preparation, time of analysis and setting up, difficulty and reproducibility.