Analytical Method: Antimony in water and wastewater

Instruments:
Cat.No. 173016  Spectroquant® Vis Spectrophotomter Prove 100 or
Cat.No. 173017  Spectroquant® UV/VIS Spectrophotometer Prove 300 or
Cat.No. 173018  Spectroquant® UV/VIS Spectrophotometer Prove 600 or
Cat.No. 109748  Spectroquant® Photometer NOVA 30 or 
Cat.No. 109751  Spectroquant® Photometer NOVA 60
   

Reagents:
Cat.No. 101084  Aluminium chloride hexahydrate purest
Cat.No. 100573  Phosphoric acid 85 % for analysis
Cat.No. 106549  Sodium nitrite for analysis
Cat.No. 100103  Amidosulfonic acid for analysis
Cat.No. 101374  Brillant green
Cat.No. 102952  Dimethylsulfoxide for analysis
Cat.No. 108325  Toluene for analysis
Cat.No. 116754  Water for analysis
 
Reagent 1:
Dissolve 20 g Sodium nitrite in 80 ml of water for analysis.
 
Reagent 2:
Dissolve 20 g Amidosulfonic acid in 80 ml of water for analysis.
 
Reagent 3:
Dissolve 0.5 g Brillant green in 50 g of Dimethylsulfoxide.
 
Reaction:
In strongly hydrochloric acidic solution antimony(V) forms an ion associate complex as SbCl6 with brilliant green, which is extractable with toluene. Antimony(III) can be oxidized by sodium nitrite for analysis.
 
Measurement range:
Method no. 130
0.10 - 8.00 mg/l Sb at cell length 10 mm and 620 nm
 
Analysis:
Mix 4.0 ml of the sample solution with about 1.5 g of aluminium chloride hexahydrate and dissolve, add 1.0 ml of phosphoric acid 85 % and mix, add 2 drops of reagent 1, close the sample vessel, mix and leave it for 3 min, then add 2 drops of reagent 2, mix and leave it again for 2 min, add 2 drops of reagent 3 and mix, add 5.0 ml of toluene for analysis, close the vessel, shake well for 30 s, divide phases. Finally transfer the upper green solution to the measurement cell with a Pasteur pipette (Attention! Water MUST NOT get into the measurement solution) and determine immediately against a blank in 10-mm cells.
 
Interferences:
According to the literature mentioned below tin, gold and thallium interfere due to the same reaction.

Measurement:
In the photometers Prove 100, Prove 300, Prove 600, Pharo 100, Pharo 400 and NOVA 60 the method is stored. For the measurement select method no. 130 in the instrument.
 
Literature:
Stanton, R.E.- J.McDonald: Analyst 87 (1962)299

Materials

     
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