Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
39, Number 3, March 2001, pp. 101-112
Analytical
Method Development for 18 Pesticides in House Dust and Settled Residues Using
SEC, SPE, TMS Methylation, and GC–MS Song
Hong, Jooyoun Kim, Ann T. Lemley*, S. Kay Obendorf, and Alan Hedge
College of Human Ecology, Martha Van Rensselaer Hall, Cornell University, Ithaca,
NY 14853
An analytical
method is developed to analyze eighteen pesticides in carpet dust and also dust
that has settled on surfaces in order to determine the potential exposure of
children to pesticide residues. For nonacid pesticides, the extract after centrifugation
and filtration is cleaned up using size-exclusion chromatography (SEC) and then
analyzed by gas chromatography (GC) coupled with a mass spectrometer (MS). The
best solvent for extraction is ethyl acetate–cyclohexane (3:1). The recoveries
of spiked nonacid pesticides from 2 g of dust are between 72% and 110% with
a variation between 4.2% and 25.6%, and the detection limit is 10 to 50 ng/g
dust, depending on the pesticide. For acid pesticides, the dust is extracted
with a saturated Ca(OH)2 solution, centrifuged, cleaned up by polyvinylbenzene/polystyrene-type
solid-phase extraction cartridges, and methylated with trimethylsilyldiazomethane
(TMS). Acid pesticides on filter paper samples are extracted with acidified
acetone (3mM H3PO4) and methylated with TMS. Methylation with TMS is fast and
easy to perform. Methyl esters of the pesticides are completely separated and
detected at low levels by GC–MS in the selective ion monitoring mode. The
average recoveries of pesticides from 2 g of dust are between 81% and 104%.
The average recoveries of pesticides spiked on filter paper are between 88%
and 113%. A capillary column with a stationary phase of trifluoropropylmethyl
polysiloxane gives the best separation and sensitivity for most pesticides on
the GC–MS.
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