ANALYSIS OF PHTHALATE ESTERS IN OYSTER TISSUE 
Procedure 
1. Whole oysters were collected from the Chester River and 
pooled according to sampling site. The number ranged 
from 4 to 8 individual oysters per site. 
2. The pooled tissue was homogenized with a Virtis "23" 
homogenizer for one minute at low speed followed by 
two minutes at medium speed. 
3. The homogenized tissue was then disrupted with a 
Branson W185 ultrasonic probe for 10 minutes. 
Light microscopy showed that this caused complete cell 
disruption. 
4. The ultrasonic probe was cleaned by running the device 
twice in distilled water and once in methylene chloride. 
The homogenizer flask and blades were then rinsed with 
water, methanol, and methylene chloride. Blanks of 
water were run between tissue preparation to check for 
contamination. 
5. Twelve to fifteen g of tissue from each site plus two 
controls prepared from commercial oysters were placed 
in 50-ml Erlenmeyer flasks, shell frozen, and placed 
in a vacuum desiccator. 
6. The desiccator was attached to a Virtis lyophylizer and 
the dry tissue was dried in 24 hours. 
7. The dried tissue was removed from each flask, pulverized 
with a mortar and pestle/ and stored at 3°C. 
8. Two hundred mg of dried tissue was placed in 10-ml vials. 
A 10 yg aliquot of anthracene d-10 was added with a 
Corning disposable micro pipette (+0.5 oercent ac¬ 
curacy) . Five ml of methylene chloride was added. 
9. The tissue was extracted using ultrasonic agitation 
(Bransonic 220 water bath) for 5 min. 
10. The vials were centrifuged at 4,000 rpm for 15 min. to 
sediment the remaining tissue residue. The supernatant 
was drawn off. The sample was concentrated by solvent 
evaporation to a volume of approximately one milliliter. 
11. The concentrated extract was injected directly in the 
GC-MS with a 25M capillary column coated with SE-52. 
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