Pure and modified water assisted by auxiliary energies: An environmental friendly extractant for sample preparation

The growing trend both to avoid the use of organic solvents and reduce the time needed to extract pollutants from environmental solid samples has led to the use of water assisted by auxiliary energies for leaching. The most common of the auxiliary energies used are high pressure–high temperature, microwaves and ultrasounds. One of the most interesting aspects of the use of water in combination with auxiliary energies is the possibility of coupling extraction with other steps of the analytical process, thus enabling partial or total automation of the analytical process, so it is expedited. The addition of reagents (such as surfactants, acids, etc.) to water enlarges its field of application and provides an additional way of shortening the leaching time; thus allowing the establishment of environmental friendly methods. A review about the potential of water as extractant and its main applications so far is here presented.