Sometimes, solid samples are difficult to analyze due to the need
to transfer the target analytes to a liquid phase. Leaching the analyte
(i.e., solid–liquid extraction or lixiviation) is one of the easiest, most
widely used sample treatments. Classically, leaching has been widely
carried out by maceration, based on the correct choice of solvents
and the use of room temperature or controlled temperature and/
or agitation to increase the solubility of compounds and the rate
of mass transfer. In general, heating the system increases the solubilization
power of the reagents or solvents used, but involves
environmental side-effects (i.e., energy consumption). Despite the
extensive use of leaching, it is characterized by long extraction protocols
with low efficiency.