The precision of the method was evaluated using the standard deviation, RSD, of repeated determinations of the
analytes and for all elements RSD ranged from 0.5 to 7% except for Na 12%. The intermediate precision (b 4.8%),
the day-to-day reproducibility (b 6.8%), and the overall uncertainty of measurement (approx. 4–10%) for all
elements analyzed demonstrated the good applicability of the chosen microwave assisted digestion procedure