Analysis of the legislated metals in different categories of olive and olive-pomace oils

Abstract

The determination in olive oils of the legislated metals (As, Cu, Fe and Pb) by the International Olive Oil Council (IOC) has been carried out by inductively coupled plasma mass spectrometry (ICP-MS) following microwave digestion with nitric acid. The method has been validated using an oil reference material and by recovery experiments, obtaining in both cases satisfactory results. The detection limits achieved are 0.9, 1.5, 3.0 and 40 ng g −1 for Pb, Cu, As and Fe, respectively. These limits are much lower than the Maximum Residue Levels permitted. The four trace metals have been determined in different categories of olive oil fit for consumption by IOC (extra virgin olive oil, virgin olive oil, olive oil and pomace-olive oil) observing a high content of Cu in pomace-olive oil. To the best of our knowledge, this is the first time that the content of the legislated metals is studied in the categories of olive oil fit for consumption.