However, the efficiency of such traditional techniques depends
on the food type. Those with high percentages of fats or proteins generate incomplete digestion due to the low oxidation potential
of nitric acid at temperatures at about 200 8C. In these cases the use
of a mixture of acids is required, demanding additional work. So
sample digestion is considered time-consuming and generally
requires large amounts of reagents, which generate hazardous
waste and increase the risk of sample contamination. Besides, the
procedures must be carried out in appropriate vessels and then the
digested volume made up in other flasks, steps in which analyte
losses can occur.