The three different techniques of extraction employed in this experiment (sonication, PLE with
off-line clean-up and SPLE) uniformly gave lower recovery
for -endosulfan.
Thermal effects on -endosulfan from PLE
and GC conditions have already been ruled out [19,27].
Therefore,
reasonable justification for the lower recovery observed
may not be inadequate analytical methods of extraction rather
it could possibly be due to the conversion of -endosulfan into
the major metabolite through time within the certified reference
soil sample itself [19].