SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

M19
METHOD DEVELOPMENT OF MICROWAVE-ASSISTED EXTRACTION AND
SUPERCRITICAL FLUID EXTRACTION OF SOME PERSISTENT ORGANIC POLLUTANTS
IN HUMAN SEBUM
Diaz-Vazquez, Liz M.*; Garcia, Oscar; Madero, Mayraliz; Velazquez, Zorangelys; and Rosario, Osvaldo,
Department of Chemistry, University ofPuerto Rico, Rio Piedras Campus, P.O. Box 23346, San Juan, P.R.,
00931-3346
Sebum has been used to monitor use of controlled drugs as well as exposure to dioxins. Based on this, it is
logical to extrapolate its use to also monitor exposure to other environmental pollutants. Methodology is
being pursued which will allow the analysis of persistent organic pollutants (POPs) through sebum testing.
Statistical Analysis methods based on Minitab® software were applied to optimize microwave-assisted
extraction (MAE) and supercritical fluid extraction (SFE) conditions for the analysis of some standards
representative of POPs. For practical purpose a model matrix of synthetic sebum spiked with the following
standards: 1,4- benzodioxan, 1,2,4, 5- tetrachlorobenzene, aldrin, dursban and pyrene was used for the
optimization of the extraction techniques. A stock solution of the model matrix was prepared as follow:
synthetic sebum was dissolved in dichloromethane and the standards of interest were spiked into the
solution. An aliquot 31lL of the spiked sebum solution was taken, deposited on the sebutape® and the
solvent allowed to evaporate. The final concentration of the standards, if a 100 % recovery was obtained,
was 3 ppm. The Recoveries of analytes were followed using GC-MS. All compounds were successfully
extracted from sebum with recoveries ranging from 69 for 1,4 -benzodioxan to 91 % for dursban under the
optimum MAE conditions: 5 mL acetonitrile, 70°C extraction temperature, and 10 min microwave heating.
The average recoveries in SFE ranging from 84 for 1,4-benzodioxan to 95 % for pyrene under the
following conditions: 30 min of extraction at 40°C, under CO 2 at 4000psi modified with 20% (v/v)
methanol. The addition of a small volume (10-20 %) of methanol to the extraction cell enhanced the
recoveries of representative persistent organic pollutants. A comparison of MAE, SFE was also conducted.
The results indicated that ~ 69 % average recoveries were obtained by both optimized techniques. Good
precision with RSD less than 10% was attained for most of the standards with both techniques. Although
with SFE higher percents of recoveries were obtained, it also is more efficient extracting the components of
the sebum like saturated hydrocarbons and fatty acids than MAE. In addition to further optimizing our SFE
approach, both MAE and SFE are now being compared with ultrasonic extraction commonly used for the
extraction of biological matrices. Solid phase extraction, with different stationary phases, was used to
remove sebum components from the extract. Also SPME was tested to improve the detection limits. Real
samples of human sebum are being analyzed from an area impacted by the emission from an incinerator of
biomedical wastes. The compounds found in these persons will be compared to compounds found in air
samples from the same region. This will show if specific air pollutants are being incorporated by this
population. Once completed and validated this noninvasive approach will provide a powerful method for
monitoring exogenous compounds in human.
Keywords: Microwave-Assisted Extraction, Supercritical Fluid Extraction, Sebum
Page 302