Focused-microwave-assisted strategies for sample preparation

In this work a general discussion is presented about extraction and digestion procedures, assisted by focused-microwave radiation. Applications involving inorganic, organic, and organometallic analytes in different types of samples are presented, taking into account recent literature data. The main advantages of using focused-microwave radiation are highlighted, such as safety, versatility, control of microwave energy released to the sample, and programmed addition of solutions. All these features can be applied properly in sample preparation for speciation analysis. New routes of development are discussed considering partial digestion by acid-vapor and gradual addition of a liquid sample to hot concentrated acids. Some preliminary results using these strategies are presented to demonstrate their potentiality.