Optimized pretreatment for accurate determination of elemental composition of extra virgin olive oil (EVOO) using ICP-OES and ICP-MS: A comprehensive study

Precisely identifying trace elements within vegetable edible oils remains a significant analytical problem due to their low concentrations and the complex composition of the matrixes. The objective of this research was to develop an analytical approach for quantifying Al, Be, Co, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Sb, Se, V, Zn, and REEs using inductively coupled plasma optical emission spectroscopy (ICP-OES) and high resolution ICP mass spectrometry (HR-ICP-MS), according to their concentration, in 13 Italian extra virgin olive oils (EVOOs). To determine the most efficient sample preparation technique, different type of pretreatment were tested, and validated by testing a certified reference material (SRM NIST 1573a). The sample manipulation involved the following steps: i. agitation for 120 min; ii. sonication for 10 min; iii. mineralization with 4 mL of HNO3 and 2 mL of H2O2 for 240 min at room temperature. Principal component analysis (PCA) was conducted to assess whether oils from different regions would separate based on their inorganic content.