14 



E 





UJ 



o: 

 o 



UJ 

 N 

 UJ 

 UJ 



O 2 

 o 



UJ 



2nd weight 

 — I St weight 



X 100 = 50.5 t 7.57o • • 



•V. 



.••• •• 



• • 





1 



1 



4 8 12 16 20 24 28 



FIRST FREEZE DRIED WEIGHT (mg) 



Figure 5-3. First freeze-dried \A«ight versus the second freeze- 

 dried weight of Neanthes arenaceodentata samples. 



The elution efficiency (EE) of the first extraction, versus the total Cu 

 present in the worms, was calculated by the following equations: 



EE%^ 



C 



IM 



xlOO 



where Cj = C^j^ + (€3^ - €2^) + (C3M - C^^) 



and Cj = Total mass of Cu 



= Measured Cu mass in the (A) vial 

 = Measured Cu mass in the (B) vial 

 = Measured Cu mass in the (C) vial 

 = Calculated Cu mass in the (B) vial 

 = Calculated Cu mass in the (C) vial 



'3M 

 '2C 

 ^3C 



The calculated EE% of Cu for this set of samples was 97.8 ± 1.8 percent. 

 Therefore, for all practical purposes of analysis for environmental samples, the 

 first extraction of the worms vath 5 percent HNO3 is essentially complete for 

 Cu. 



66 



