Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
38, Number 9, September 000, pp. 399-408
Extraction
of Atrazine and Its Metabolites Using Supercritical Fluids and Enhanced-Fluidity
LiquidsMichael E. Shows and Susan V.Olesik Department of Chemistry and Environmental Science Program, The Ohio
State University, 100 West 18th Avenue, Columbus, OH 43210
Supercritical
fluid and enhanced-fluidity liquid extractions are performed on spiked sediment
samples containing atrazine (ATRA) and five of its metabolites including desisopropyldesethylatrazine,
desethylhydroxyatrazine (DEHA), desisopropylatrazine, desethylatrazine, and
hydroxyatrazine (HA). The hydroxylated metabolites are of particular interest
because of their increased water solubility and the fact that their high polarity
makes them difficult to analyze. Soxhlet extractions using methanol are conducted
for the purpose of comparison. Results of the extractions show that the hydroxy-containing
metabolites of ATRA are not effectively extracted with supercritical CO2 alone.
The solvating or desorbing power of carbon dioxide appears too low to extract
HA and DEHA. The extraction recoveries of the hydroxylated metabolites increase
when enhanced-fluidity liquid mixtures of methanol/CO2 are used, and these rates
increase with the methanol concentration. Enhanced-fluidity ternary liquid mixtures
of H2O/methanol/CO2 yield the best recoveries for these compounds. ATRA recoveries
are equally effective when using supercritical CO2 or enhanced-fluidity mixtures.
The other nonhydroxy- containing metabolites require the increased solvent strength
of either large percentages of methanol in CO2 or ternary mixtures of H2O, methanol,
and CO2 for high recoveries. Recoveries with enhanced-fluidity liquid ternary
mixtures are better than the recoveries from Soxhlet for all the compounds in
the study.
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