## 1 Introduction  
Vegetable oils are essential food products of high nutritional value and a major agri-food commodity subjected to adulteration before commercialization. Consumers are appreciating oils' nutritional potential but are concerned about their quality and safety, while the food producers are careful to their quality, influenced by multiple environmental and technological factors affecting mostly the fatty acids, such as oxidation and higher levels of trans derivatives [1, 2, 3]. Over the years, the Codex standards for fats and oils have been modified to enhance the supervision of vegetable oils quality and authenticity, and available databases and international standards are evolving ([[https://www.fao.org/3/t4660t/t4660t0e.htm](https://www.fao.org/3/t4660t/t4660t0e.htm)]([https://www.fao.org/3/t4660t/t4660t0e.htm](https://www.fao.org/3/t4660t/t4660t0e.htm)) accessed 15 January 2021). The EU legislation by Regulation (EEC) 2568/91 established methods for olive oil analysis, but not for other types of vegetable oils. Meanwhile, in the context of the fight against food fraud, the publication of EU regulation 2017/625 focused on legal regulations related to edible oils. Authenticity is a very important quality criterion, considering the significant differences of composition, safety, and price between the cold-pressed (extra virgin, virgin) and refined oils, as well the mislabeling of commercial products. Moreover, along with olive oils, other edible oils are considered functional or specialty (e.g., pumpkin, walnut, soybean, hep, linseed, sea buckthorn), since, beside the nutritional function, they contain bioactive compounds with health benefits and reduced risk of some diseases, mainly cardiovascular and neurovegetative, due to their high amounts of essential polyunsaturated lipids rich in linoleic acid and linoleic fatty acids, phospholipids, phytosterols, and bioactive phenolics [4]. Edible vegetable oils contain mainly triacylglycerlycerols (up to 98%) and different phytochemicals (micronutrients) as tocopherols, phytosterols and carotenoids, essential components for our diet, having high nutritional value. The most consumed edible oils in Central and Eastern Europe are sunflower, soybean, rapeseed oils, but also increasingly olive, pumpkin, grapeseed and palm oils [5; 6]. Most publications related to the identity (quality and authenticity) of oils are dominated by studies on different olive oil varieties and commercial quality. The health benefits of olive oil are well documented, being mainly attributed to their high content in monounsaturated fatty acids (MUFAs), e.g., oleic and palmitoic acids, but also to sterols, carotenoids, tocopherols and polyphenic compounds (tyrosol derivatives and oleuropein), all being known for their antioxidant activity [7; 8; 9; 10; 11; 12; 13]. These natural antioxidants are found in many other functional oils, but fewer data were available regarding their composition and identity, dependent on their botanical phenotype and geographical distribution. Metabolomics is an advanced technology which offers a comprehensive characterization of small, bioactive molecules (phytochemicals) which play a central role in oils' identity. Analytical platforms such as gas chromatography and liquid chromatography coupled with diode array, fluorescence or mass spectrometry-detection techniques (GC-MS and LC-DAD-RF-MS) and nuclear magnetic resonance (NMR) spectroscopy are essential prerequisites used to ensure a systematic study about the quality and authenticity biomarkers of vegetable oils. Mainly, chromatography is applied for the separation and mass spectrometry for identification. The GC-MS is a standardized method to identify and quantify fatty acids, volatile components, and sterols, while LC-DAD-RF-MS or fluorescence (HPLC-RF) are useful for the separation, identification and quantification of carotenoids, tocopherols and polyphenols ([14; 15; 16; 17; 18; 19; 20; 21; 22].