Ultrasound-assisted digestion: a useful alternative in sample preparation.

Ultrasound-assisted digestion is a promising alternative in the analysis of solid samples when either simple dissolution or direct analysis is not applicable. However, the field of application of ultrasonic sample digestion is still small in comparison with classical digestion alternatives and, particularly, with microwave-assisted digestion. This fact can be justified by the scant knowledge analytical chemists have about the advantages ultrasonic energy provides to digestion. Among these, the strict control at low temperatures of ultrasound applications allows the implementation of ultrasonic-assisted steps in biochemical analyses. In this connection, two specific biological applications, ultrasonic enzymatic digestion and assistance of ultrasound for cell disruption, are also reviewed.