V. Lopezavila et al., EVALUATION OF SOXTEC EXTRACTION PROCEDURE FOR EXTRACTING ORGANIC-COMPOUNDS FROM SOILS AND SEDIMENTS, Journal of AOAC International, 76(4), 1993, pp. 864-880
A study was carried out to evaluate the Soxtec extraction of 29 target
compounds (7 nitroaromatic compounds, 3 haloethers, 7 chlorinated hyd
rocarbons, and 12 organochlorine pesticides) from spiked sandy clay lo
am and clay loam. The study also compared 2 solvent mixtures (hexane-a
cetone (1 + 1) and methylene chloride-acetone (1 + 1)) and investigate
d the effect on method recovery of 5 factors (matrix type, spike level
, anhydrous sodium sulfate addition, total extraction time, and immers
ion/extraction time ratio), their 2-way interactions, and a 3-way inte
raction (matrix x spike x time). Of the 5 factors investigated, matrix
type, spike level, and total extraction time had a significant effect
on method performance at the 5% significance level for 16 of the 29 t
arget compounds (4 compounds were not recovered at all, and analysis o
f variance was not significant at the 5% significance level for 9 comp
ounds). Anhydrous sodium sulfate addition and immersion/extraction tim
e ratio had insignificant effects for all but one of the target compou
nds. This effect may have been a random occurrence. The data indicate
that the 2 solvents performed equally well and 4 compounds were not re
covered at all. These 4 compounds were apparently lost from the spiked
matrix. Experiments were performed to determine compound recovery at
each step in the extraction procedure. Limited experimental work was p
erformed with 64 basic/neutral/acidic compounds spiked onto clay loam
and with 3 standard reference materials certified for polynuclear arom
atic hydrocarbons. From the 64 compounds spiked onto clay loam at 6 mg
/kg, 20 had recoveries of greater than 75%, 22 had recoveries from 50
to 74%, 12 had recoveries from 25 to 49%, and 10 had recoveries of les
s than 25%.