NSWC/WOL/TR 75-3 5 



a. Sample handling 



For the determination of dissolved constituents the sample 

 should be filtered through a 0.45 y membrane filter as soon as 

 practicable after collection. Acidify the filtrate with 1:1 HNO3 

 (3 ml per liter). Normally this amount of acid will lower the pH to 

 2 or 3 and should be sufficient to preserve the sample indefinitely. 



b. Concentration 



Aluminum 



A method for the concentration of Al in water has been 



developed by Hsu and Pipes. 23 i n their method, a benzene solution 



of diphenylthiocarbazone (0.1% by wt.), 8-quinolinol (0.75% by wt . ) , 



and acetylacetone (20% by vol.) is used to extract Al from water. 

 The optimum pH for extraction is about 5. An extraction ratio as 



high as 200 (1000 ml aqueous sample and 5 ml benzene solution) can 



be conveniently used. A sensitivity of 9 yg/1 can be attained by 

 this method. 



Lead 



A procedure has been developed by Brooks et al for the 

 extraction of Pb from saline waters. 24 The procedure should be 

 applicable to fresh waters as well. In the procedure samples of 

 seawater (750 ml) are placed in 1000 ml Erlenmeyer flasks and 35 ml 

 of methyl isobutyl ketone (MIBK) are added to each flask followed by 

 7 ml of 1% ammonium pyrollidine dithiocarbomate (APDC) solution. The 

 samples are then equilibrated for 30 min. on a mechanical shaker. 

 The phases are separated by means of a separatory funnel and the 

 organic phases are stored in polyethylene bottles. With this 

 procedure a sensitivity of 2 Ug/1 can be attained. 



9 -j 



Hsu, D. Y. and Pipes, W. 0., "Modification of Technique for 



Determination of Aluminum in Water by Atomic Absorption 

 Spectrophotometry", Environ. Sci, Technol., 6, 654 (1972). 



24 Brooks, R. R., Presey, B. J., and Kaplan, I. R. , "APDC-MIBK 



Extraction System for the Determination of Trace Elements in Saline 

 Waters by Atomic-Absorption Spectrophotometry", Talanta, 14, 809 

 (1967) . 



49 



