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Abstract
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In this study, a simple, rapid, and an economical
method has been proposed for the extraction, preconcentration,
and determination of parabens (methyl-, ethyl-,
and propylparaben) in different samples based on derivatization
by acetic anhydride and preconcentration using airassisted
liquid–liquid microextraction in a single step. In
this method, 1,1,2,2-tetrachloroethane (extraction solvent)
containing μL-level of acetic anhydride (derivatization
agent) is injected into aqueous sample containing parabens
and picoline (catalyst). The mixture of aqueous and
organic phases is withdrawn into a glass syringe and then
injected into the test tube for several times till a turbid solution
is obtained. After centrifuging, 1 μL of the sedimented
phase is injected into gas chromatography-flame ionization
detector. The effect of catalyst volume, derivatization
agent volume, extraction solvent type and volume, ionic
strength of the solution, pH, and numbers of extraction on
the extraction efficiency is investigated. Under the optimal
conditions, the enrichment factors and enhancement factors
for the parabens were obtained in the ranges of 310–353
and 2,484–5,298, respectively. Limits of detection were
between 0.18 and 8.5 μg L−1. The method was found to
be linear over the range of 10–10,000 μg L−1 with good
coefficients of determination (R2 > 0.999). The obtained
extraction recoveries ranged from 69 to 107 % and precision
of the method, expressed as relative standard deviation
(RSD %), was within the range of 4.0–13 %. The proposedmethod was successfully applied for determination of parabens
in different samples such as cream, toothpaste, and
mouthwash.
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