Regarding organic solvent consumption, in the SLE
method (9.3mL per sample), it is considerable lower than
in the PLE method (more than 50mL per sample). In relation
to the time of analysis, although the chromatographic analysis
(85 min) is the limiting step, the SLE method allows to
extract a large number of samples simultaneously in 10 min
(plus the time used for adding the extraction solvent to each
sample). Instead, the ASE 200 (Dionex Corp., Sunnyvale,
CA, USA) equipment used in the PLE method performs the
sample extractions consecutively, the time used for each extraction
being 20 min. Moreover, the time for preparing the
extraction cells also has to be considered. This drawback is
partially solved, since PLE is an automated technique