Quality control and quality assurance of the analytical work were approached 
through a three-tiered program. The first tier included the use of 
multiple analyses, blanks, standards additions, and primary standards. 
The second tier included review of laboratory practices and the application 
of splits, blanks, blinds, and replicates to guarantee performance. 
The third tier included periodically introducing blinds from outside 
laboratories and participation in round-robin proficiency testing 
programs with other laboratories. 
Trace organics analysis . Preweighed samples (approximately 10 g) were 
chopped and slurried with approximately 200 ml methylene chloride. Soxhlet 
extracted/activated anhydrous granular sodium sulfate (50 g) was added 
and the mixture ground for approximately 5 minutes using a Brinkman 
Polytron sonicating tissue homogenizer with PT 35K probe. After initial 
homogenization, each sample was spiked with 100 ul o,p'-DDE, perdeuterated 
perylene.The sample was then homogenized further using the PTIO probe. 
Additional sodium sulfate was added until the sample was efficiently 
dehydrated as indicated by the persistence of free granular sodium sulfate. 
When homogenization/dehydration was complete, the slurry was transferred 
to a fritted glass extraction thimble containing a bed of anhydrous sodium 
sulfate. The filled thimble was then transferred to a Soxhlet continuous 
extractor charged with 350-500 ml methylene chloride and extracted for 
24 hours. The extract was replaced with fresh solvent and the sample was 
reground and repacked in the thimble, with fresh sodium sulfate added as 
necessary, then extracted for an additional 24 hours. Careful Polytron 
cleaning, inspection and homogenization of blank solvent were used to 
ensure no cross-contamination between samples. The extracts were combined, 
concentrated to less than 10 ml, filtered through a 1 urn Gelman Acrodisc 0 
and diluted to exactly 10 ml, and a 5% aliquot removed for extracted 
residue weight determination. The remaining extract was concentrated to 
1 ml and diluted with 1 ml pentane prior to size exclusion preparative 
chromatography. Residue weights were determined by air drying to constant 
weight in a tared aluminum boat. 
Size exclusion chromatography (SEC) . SEC columns (SX-2 Biobeads, Biorrad, 
Inc.) were individually calibrated using a standard mixture containing 
hexachlorobutadiene, hexachlorobenzene, o,p'-DDE, p,p'-DDE, o,p'-DDD, 
p,p'-DDD, o,p'-DDT, p,p'-DDT, plus several PCB isomerids and several PAHs. 
They were eluted isocratically with 50% methylene chloride, 50% pentane 
solvent. Initial elution of the priority compounds (indicated by hexa- 
chloro-1,3-butadiene) typically began at 90-95 ml, with some non-target 
compounds (such as pthalates) and considerable biological background 
eluting in the 70-90 ml fraction. Three fractions were collected: 0-70 ml 
("FI", discarded or archived), 70-90 ml ("F2", archived), and 90-350 ml 
("F3", for further analysis). The elution behavior of each sample was 
verified by detection of fluorescent components (perdeuterated perylene 
plus endogenous PAH) with UV handlight, in a 150-250 ml elution volume range. 
Prepared extract concentrate (2 ml) in 50/50 methylene chloride/pentane 
was loaded on the SX-23 column bed, and the collection of eluate was begun. 
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