Preparation of stock solution B 
Stock solution B was made by adding 10 mL of butyl acetate (distilled to 
remove impurities such as copper) to 15 mL of stock solution A in a 60-mL 
separatory funnel. This solution was vigorously agitated by an automatic 
shaker for six minutes to extract iron. The layers were separated, and the 
extraction step was repeated with an additional 10 mL of butyl acetate. The 
aqueous layer was evaporated to dryness at 150°C in a 50-mL beaker. The 
residue was dissolved and diluted to 25 mL with 1 N HCl. 
Barium 
The measurements for Ba were made by ICP spectrometry with 2 mL of stock 
solution A diluted to 4 mL with distilled H 0. 
Aluminum, iron, chromium, nickel, and vanadium 
Concentrations of Al and Fe were determined by ICP spectrometry by using 
1 mL of stock solution A diluted to 10 mL with HO. The measurements for Cr, 
Ni, and V were made by injecting 20 wL of diluted (1:10) stock solution A into 
a graphite-furnace AA spectrophotometer. 
Lead, copper, and cadmium 
Fifteen mL of 0O.5-percent (weight: volume) diethyldithiocarbamic acid 
diethylammonium salt (DDTC) in chloroform were added to 10 mL of solution B in 
a 60-mL separatory funnel and mixed for 10 minutes by an automatic shaker. 
The chloroform layer was drained into a 30-mL beaker and the aqueous layer 
washed with 10 mL of chloroform. The second chloroform layer was combined 
with the first, and the total volume of chloroform was evaporated to dryness 
at 90°C. The organic matter was destroyed by adding 0.1 mL of concentrated 
HNO3 and was evaporated to dryness. This residue then was dissolved in 2 mL 
of warm 1N HCl. The beaker was rinsed four times with 2 mL portions of 
distilled Hy0, and the solution was transferred to a small polyethylene 
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