Influence of digestion methods on the determination of total Al in food samples by ICP-ES

Summary To determine total Al in a variety of food and total diet samples using ICP-ES, HF pre-treatment, prior to wet digestion (HNO₃/HClO₄) seems to be necessary. Compared with results obtained after HF pre-treatment, the determination of Al using pressure microwave digestion with HNO₃ or HNO₃/HClO₄ digestion recovered only between 25–50% Al for dried spinach and flour and 40–75% for total diet samples, respectively. In most cases the addition of 0.25 ml HF (40%) per gram dry mass resulted in maximum Al yield. The results are in acceptable agreement with those obtained by neutron activation analysis (NAA).