Determination of arsenic species distribution in extra virgin olive oils from arsenic-endemic areas by dimensional chromatography and atomic spectroscopy

Abstract

Arsenic species were determined in extra virgin olive oils (EVOOs) by two dimension chromatography and atomic spectroscopy: inductively coupled plasma mass spectrometry (ICP MS) and electrothermal atomic absorption spectrometry (ETAAS). A first approach determined total As concentration in EVOOs samples by microwave assisted digestion and ICP MS from 2.01 to 152 μg kg−1. EVOOs with elevated As concentration were selected for protein extraction. In a first dimension, by size exclusion chromatography (SEC) coupled to ICP MS, a fraction of 66 kDa was identified and collected for analysis. Free and proteic As were separated by molecular weight cut off filters. Proteic and free arsenic concentrations determined by ETAAS range from 0.56–4.44 and 0.67-3.89 μg kg−1 of As respectively. Finally in a second dimension, by anion exchange chromatography (AEC) coupled to ICP MS, dimethylarsenate and arsenite were determined in proteic fraction of EVOOs in concentrations of 1.68–2.86 and 0.53–0.55 μg kg−1 respectively.