Evaluation of hydrocarbon contaminants in olives and virgin olive oils from Tunisia

Polycyclic aromatic hydrocarbons in edible oils: An overview on sample preparation, determination strategies, and relative abundance of prevalent compounds

“…The optimum separation conditions usually imply a solvent gradient with ACN and water. Gradients normally start with a 40% to 50% ACN, in most cases (Barranco et al, 2003;Costopoulou et al, 2010;Gharbi et al, 2017;Martinez-López et al, 2005;Payanan et al, 2013;Shi et al, 2015Shi et al, , 2018Stenerson et al, 2015;Taghvaee et al, 2016;Teixeira et al, 2007;Yousefi et al, 2018;Zhao et al, 2013); then this concentration is linearly risen to 89% to 100% in an approximate time of 45 min, as so suggests ISO 15753:2016. Some reports have indicated the use of gradients with a higher proportion of ACN (70% to 85%) at the beginning of the run (Alves da Silva et al, 2017;Camargo et al, 2011;Ergönül & Sánchez, 2013;Ji et al, 2017;Molle et al, 2017;Moreda et al, 2004;Purcaro et al, 2008;Rodríguez-Acuña et al, 2008a;Tfouni et al, 2014).…”

“…As far as the flow rate is concerned, ISO 15753:2016 recommends a value of 1.2 mL/min. Some adjustments have been made with respect to this guidance, and flow has been also set at values of 1 mL/min (Barranco et al, 2003;Camargo et al, 2011;Costopoulou et al, 2010;Ergönül & Sánchez, 2013;Gharbi et al, 2017;Ji et al, 2017;Molle et al, 2017;Moreda et al, 2004;Rodríguez-Acuña et al, 2008a;Shi et al, 2018;Tfouni et al, 2014), 1.4 mL/min (Alarcón et al, 2012;Stenerson et al, 2015), and 1.5 mL/min (Dost & Ideli, 2012;Payanan et al, 2013;Purcaro et al, 2008;Teixeira et al, 2007;Wang, Lian, et al, 2018;Zhao et al, 2013). Alves da Silva et al (2017 focused on the determination of the set of PAH4 in some cold-pressed vegetable oils, applying a lower flow rate (0.4 mL/min) and a column with the following dimensions: 100 mm × 2.1 mm × 1.8 µm.…”

“…As explained above, many authors have reported a direct application of the samples to the SPE, combining the extraction and cleaning step and avoiding the time and solvents consumed during the LLE or any other preceding step. Samples have been applied to the cartridge without any dilution (Bogusz, El Hajj, Ehaideb, Hassan, & Al‐Tufail, 2004; Chung & Lau, 2015; Stenerson, Shimelis, Halpenny, Espenschied, & Ye, 2015), or after carrying out a simple dilution with hexane (Gharbi et al., 2017; Purcaro, Moret, & Conte, 2008; Purcaro, Morrison, Moret, Conte, & Marriott, 2007) or isooctane/cyclohexane (1:2, v/v) (Cortesi & Fusari, 2006), but no previous steps (e.g., LLE, saponification, etc.) have been conducted.…”

“…have been conducted. Silica adsorbents have been preferably used, applying CH 2 Cl 2 and hexane (Gharbi et al., 2017; Purcaro et al., 2008) as activation solvents and mixtures of hexane/CH 2 Cl 2 (70:30, v/v) (Gharbi et al., 2017; Purcaro et al., 2008) or cyclohexane (Alomirah et al., 2010) as elution solvents. In the past, some authors reported the use of tetrahydrofuran as eluent solvent too (Weißhaar, 2002).…”

“…Thus, any contamination may be attributed to the contact of the olive fruit with polluted air, mineral oil residues from packaging, or with any contaminated element present in the production line (mill, transport containers, etc.) (Bansal & Kim, 2015; Gharbi et al., 2017; Guillén et al., 2004; Rodríguez‐Acuña, Pérez‐Camino, del, Cert, & Moreda, 2008b).…”