Avoiding any kind of oil sample pretreatment, a fraction containing the steryl glucosides (SG) was directly isolated by SPE. This fraction was derivatised and analysed by GC in order to quantify the SG content. The limit of detection of the method was 0.37 mg/kg and the recovery 90%. Additionally, the identity of the SG was confirmed by MS. We applied the procedure to oil samples of different categories and origins indicating that the only SG that could be quantified in olive oil was β-sitosteryl glucoside, which was present at concentrations not higher than 3.00 mg/kg.
Practical applications: Olive oil is of upmost importance from both the nutritional point of view and from the economic repercussion that fraud may have. Among the many parameters required by the EU in order to determine olive oil characteristics, SG are completely overlooked and no specific methodology has been elaborated so far. We have developed a straightforward protocol for the determination of SG in olive oil. This method can be used to provide an additional identity parameter and a new blend indicator. This method is fast, cheap and easy to perform. Besides, it has a great potential for automation which would allow its routine application. The possibility of applying the procedure to study vegetable oils used in the biodiesel industry is also pointed out.