An optimized method for sample preparation and elemental analysis of extra-virgin olive oil by inductively coupled plasma mass spectrometry

Abstract

The accurate determination of trace elements in vegetable edible oils is still an analytical challenge, owing to their low concentration levels and the complex matrix of the vegetable oils. The aim of this study was to develop a fast and simple analytical method to quantify 45 elements in small mass samples (0.5 g) of extra virgin olive oils by inductively coupled plasma mass spectrometry. To evaluate the best and fastest sample preparation procedure, ultrasonic extraction and wet digestion methods were compared using oil certified reference material with different reagent mixtures, reagent volumes, and times for sample extraction or digestion. The use of 5 mL reagent mixture F [10% (v/v) HNO₃ and H₂O₂, 2:1 (v/v)] for sample digestion in a water bath (95 °C, 40 min) was found to produce satisfactory results in all cases as validated from sample recovery experiments over three different extra virgin olive oil samples.

Keywords: ICP-MS; Sample preparation; Spectroanalytical technique; Toxic trace elements; Ultrasonic extraction; Virgin olive oil; Wet digestion.