Extraction of Organochlorine Pesticides
from Oyster Tissue Using Accelerated
Solvent Extraction
Pranathi Perati and SM Rahmat Ullah
Thermo Fisher Scientific, Sunnyvale, CA, USA
Application Brief 152
Introduction
Organochlorine pesticides (OCPs) are a class of chemicals
that were used to control insect pests since the 1940s.
The use of OCPs was banned in the later part of the last
century due to their longevity, a trait that made them
effective for long term pest control, but also increased
concerns of potential health outcomes such as cancer in
humans and ecosystem disruption. Pesticides are regulated
in the U.S. by the Environmental Protection Agency (EPA)
under the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA). Some states also regulate pesticides under
FIFRA, in a more restrictive manner than the EPA. In the
European Union, water intended for human consumption
must meet a maximum level of 0.1 μg/L for each pesticide
and a maximum of 0.5 μg/L for total pesticides, except for
aldrin, dieldrin, heptachlor, and heptachlor epoxide, which
are each limited to maximum levels of 0.03 μg/L. Maxi-
mum contaminant levels have been established for OCPs
by the United States Environmental Protection Agency
ranging from 0.2 μg/L for Lindane to 2 μg/L for Endrin.
Many OCPs are endocrine disrupting chemicals, meaning
they have subtle toxic effects on the body’s hormonal
systems. Endocrine disrupting chemicals often mimic the
body’s natural hormones, disrupting normal functions
contributing to adverse health effects. OCPs are persistent
organic pollutants (POPs), a class of chemicals that are
ubiquitous environmental contaminants because they
break down very slowly in the environment and accumu-
late in lipid rich tissue such as body fat. According to the
Centers for Disease Control and Prevention (CDC), most
people have OCPs present in their bodies. Exposure to
low concentrations of organochlorine chemicals over a
long period may eventually lead to a substantial body
burden of toxic chemicals. Organochlorine compounds
have long been recognized as the most deleterious
contaminants to biota in the world's marine and estuarine
waters. Various biomonitoring strategies have therefore
been developed to monitor and evaluate the adverse
impact of these compounds on the marine ecosystems.
Analyses of OCPs are becoming increasingly important,
and often with the need to isolate and analyze trace levels
of compounds from a variety of matrices such as soil,
sediment, animal tissue, fruits, and vegetables. Sample
pretreatment constitutes an important step prior to
analysis. The purpose of the sample pretreatment step
is to selectively isolate the analytes of interest from
matrix components and present a sample suited for
routine analysis by an established analytical techniques
such as gas chromatography or high-pressure liquid
chromatography. Accelerated solvent extraction is an
established technique for extracting analytes of interest
from a solid, semisolid or an adsorbed liquid sample
using an organic solvent at an elevated temperature and
pressure. The elevated pressure elevates the boiling
temperature of the solvent thereby allowing faster
extractions to be conducted at relatively high tempera-
tures. Thus the extraction process is significantly faster
than traditional methods such as Soxhlet extraction.
This Application Brief discusses the use of Thermo
Scientific
™
Dionex
™
ASE Prep MAP, a proprietary polymer
designed to remove moisture and increase extraction
efficiencies from wet samples including soils, tissues and
food products. This polymer is useful for in-cell extraction
of trace level organics from a variety of moisture containing
samples with no additional pre or post extraction steps.
The Dionex ASE Prep MAP polymer has a high-capacity
for water removal and does not suffer from some of the
limitations of clumping or precipitation observed in some
of the traditional drying methods.
Key Words
Persistent organic pollutants, moisture absorbing polymer, wet samples,
accelerated solvent extraction, sample preparation
