Ambient mass spectrometry employing direct analysis in real time (DART®) ion source for olive oil quality and authenticity assessment

Authors: Vojtech Hrbek, Jana Hajslova , Lukas Vaclavik, Tomas Cajka
Analytica Chimica Acta 2009, May, 05, 645(1-2), 56–6
doi:10.1016/j.aca.2009.04.043

 

A novel approach for the authentication of olive oil samples representing different quality grades has been developed.Anewtype of ion source, direct analysis in real time (DART®), coupled to a high-resolution time of- flight mass spectrometer (TOFMS) was employed for the comprehensive profiling of triacylglycerols (TAGs) and/or polar compounds extracted with a methanol–water mixture. The main parameters influencing the ionization efficiency of TAGs were the type of sample solvent, degree of sample dilution, ion beam temperature, and presence of a dopant (ammonia vapors). The ionization yield of polar compounds depended mainly on a content of water in the extract and ion beam temperature. Using DART®–TOFMS,not only differentiation among extra virgin olive oil (EVOO), olive pomace oil (OPO) and olive oil (OO)could be easily achieved, but also EVOO adulteration with commonly used adulterant, hazelnut oil (HO),was feasible. Based on the linear discriminant analysis (LDA), the introduced method allowed detection
of HO addition of 6 and 15% (v/v) when assessing DART®–TOFMS mass profiles of polar compounds and TAGs, respectively.