Pressurized hot water extraction coupled to molecularly
imprinted polymers for simultaneous extraction and clean-up
of pesticides residues in edible and medicinal plants of the
Okavango Delta, Botswana
, Shima Batlokwa
, Keta Mosepele
, Veronica Obuseng
, and Nelson Torto
1 Department of Chemistry,
Rhodes University, P O Box 94,
Grahamstown, 6140, South Africa
2 Department of Earth & Environmental
Science (Chemistry Unit), Botswana
International University of Science
& Technology, P.O. Box 041, Bontleng,
3 University of Botswana - Okavango
Research Institute, Private Bag 85,
4 Department of Chemistry,
University of Botswana,
Private Bag 00704, Gaborone,
In this study, an in-cell extraction and clean-up approach, employing
pressurized hot water extraction (PHWE) coupled to a molecularly imprinted
polymer (MIP) is proposed. The selectivity of PHWE was improved
through the use of a chlorophyll MIP (PHWE-MIP) for the determination of
organochlorine pesticides residue levels in various edible and medicinal
plants of the Okavango Delta, Botswana. The PHWE-MIP method achieved
simultaneous extraction and clean-up. PHWE employed an optimal
temperature of 260 °C, pressure of 90 bar and flow rate of 1 mL min-1
in 10 min for the extraction of the pesticides from plants while the MIP
selectively overcame the interfering chlorophyll prior to analysis with gas
chromatograph coupled to electron capture detector or mass spectrometer
(GC-ECD/MS). The results obtained were compared to the QuEChERS
Official Method 2007:01 for pesticides residue analysis. The proposed
method seems to be nearly fully automated, environmental friendly,
selective, simple and quick. Moreover, the recoveries of planar pesticides
were improved (93-95%) with relative standard deviations (%RSD) of less
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