Sample pre-treatment can be considered the most polluting step of the whole analytical process because it deals with the crude sample, in which the analytes may exist in 1000-fold smaller quantities than bulk constituents, so, often, the use of organic solvents is required to enrich the target compounds selectively and remove
potentially interfering matter.
An ideal GAC protocol avoids sample pre-treatment. However, in the majority of the cases, this is not feasible, so a plethora of strategies have been developed to obtain greener approaches