5. 6N hydrochloric acid (HC 1) - equal 

 volumes of concentrated hydro- 

 chloric acid and distilled water. 



6. Tartaric acid (C4H£,0£,) solution 

 (10 percent) - dissolve 100 gms. 

 of tartaric acid in distilled water 

 and dilute to 1 liter. 



7. IN ammonium hydroxide (NH4OH) - 

 dissolve and dilute 67 ml. of con- 

 centrated ammonium hydroxide to 

 1 liter with distilled water. 



8. Ammonium acetate (CH3COONH4) 

 buffer solution (20 percent) - dis- 

 solve 200 gms. of ammonium ace- 

 tate in IN ammonium hydroxide 

 (NH4OH) solution and dilute to 1 

 liter with distilled water. 



9. IN acetic acid (CH3COOH) - dilute 

 58 ml. of concentrated acetic acid 

 to 1 liter with distilled water. 



10. Oxine (CgHyNO, 8-quinolinol) solu- 

 tion (2 percent) - dissolve 20 gms. 

 of 8-quinolinol in IN acetic acid 

 and dilute to 1 liter with distilled 

 water. 



11. Chloroform (CHCI3). 



12. Aluminum oxide (AI2O3) standard 

 solution (500 mu gms. /ml.) - dis- 

 solve 4.4500 gms. of aluminum 

 ammonium sulfate [Al 2(804)3. 

 (NH4)2S04.24H2.0] in distilled 

 water and dilute to 1 liter. 



13. Aluminum oxide (AI2O3) standard 

 solution (25 mu gms./ ml.) - dilute 

 25 ml. of aluminum oxide standard 

 solution (500 mu gms. /ml.) to 500 

 ml. with distilled water. 



Procedure : Kenyon and Bewick ( 1952) 

 described a photometric method for 

 deternnining aluminunn as the oxinate in 

 a sample containing several other 

 metals, by complexation with 8-quino- 

 linol, manipulation of the pH and ex- 

 traction with chloroform to rennove 

 interfering ions and then to get the 

 aluminum oxinate. This is the basic 

 method used to determine the con- 

 centration of aluminum in sediments. 



Weigh about 0.2 gm . of sample into 

 a 150-ml. beaker and add 10 ml. of 6N 

 hydrochloric acid and 5 ml. of con- 

 centrated nitric acid. Heat at medium 

 setting on an electric hot plate until 

 evaporation is complete, bake for 10 

 nninutes, allow to cool and add 3 ml, 

 6N hydrochloric acid. Heat on the hot 

 plate to near boiling and filter the 

 mixture using a medium-flow filter 

 paper (Whatman No. 4) catching the 

 filtrate in a 100-ml. volumetric flask. 

 Fill flask to mark with distilled water, 

 mix well and transfer 10 ml. of the 

 solution to a 150-ml. beaker. Add 50 

 ml. of distilled water and adjust to a 

 pH of less than 4. Add 3 ml. of 10 per- 

 cent tartaric acid solution, 2 ml. of 

 ammonium acetate solution and 2 ml. 

 of oxine (8-quinolinol) solution. Mix 

 thoroughly and adjust pH to 6.6 with 

 concentrated and IN ammonium hy- 

 droxide solutions, digest 15 minutes 

 in a water bath at 65° C. and let cool. 

 Adjust the pH to 2.8 with 3N hydro- 

 chloric acid and transfer the solution 

 to a separatory funnel. Extract with 

 two 10-ml. portions of chloroform and 

 discard extracts. Return aqueous 

 solution to a 150-ml. beaker, add 1 

 ml. of oxine solution, adjust pH to 

 5.7 with concentrated and IN ammonium 

 hydroxide and digest in water bath at 

 15° C. for 15 minutes. Return solution 

 to separatory funnel and extract with 

 two 10-ml. portions of chloroform, 

 shaking the first portion 2 minutes and 

 the second for 1 minute. Filter the 

 chloroform extracts through a chloro- 

 form-wetted filter paper and catch the 

 filtrate in a 50-ml. volumetric flask. 

 Wash filter well with chloroform, add- 

 ing washings to the flask and fill to 

 mark with chloroform. 



Make a set of standards by placing 

 0-, 2-, 4-, 6- and 8-ml. portions of 

 the 25 mu gms. AI2O3 per ml. solu- 

 tion in a series of 150-ml. beakers 

 and diluting each to 60 ml. with dis- 

 tilled water. This gives solutions con- 

 taining 0, 50, 100, 150 and 200 mu 

 gms. of aluminum oxide. Adjust the pH 

 to less than 4 with 3N hydrochloric 

 acid and add 3 ml. of 10 percent 

 tartaric acid, 2 ml. of ammonium ace- 

 tate buffer, 2 ml. of oxine solution 

 and then adjust the pH to 5.7 with 



