Spectrophotometric Determination of Thorium with Eriochrome Black T. (Ethylenedinitrilo)tetraacetic Acid and 2,2´,2˝-Nitrilotriethanol as Masking Agents

1960 ◽  
Vol 32 (12) ◽  
pp. 1702-1704 ◽  
Author(s):  
P. F. Lott ◽  
K. L. Cheng ◽  
B. C. H. Kwan
Keyword(s):  
Spectrophotometric Determination ◽  
Tetraacetic Acid ◽  
Eriochrome Black T ◽  
Masking Agents

On the spectrophotometric determination of with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol

1988 ◽  
Vol 66 (3) ◽  
pp. 401-405 ◽  
Author(s):  
Lumír Sommer ◽  
Eva Šamlotová
Keyword(s):  
Spectrophotometric Determination ◽  
Natural Water ◽  
Water Samples ◽  
Sodium Sulphate ◽  
Optimum Conditions ◽  
Reaction Conditions ◽  
Masking Agents ◽  
Triton X ◽  
Sulphosalicylic Acid

2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) is a suitable reagent for the spectrophotometric determination of uranium but results are easily influenced by the reaction conditions as well as various common ions and masking agents. Optimum conditions, which must be carefully maintained, are 30% (v/v) dimethylformamide, 0.1% triton X-100, ≥ 8 × 10−5 M 5-Br-PADAP, 8 × 10−2 M triethanolamine, 7 × 10−3 M sodium fluoride, 10−2 M 5-sulphosalicylic acid, and 579 nm. Sodium sulphate (10−2 M) and CDTA (5.7 × 10−3 M) may serve as additional masking agents. A previous separation of uranium by extraction with 0.1 M tri-n-octylamine in benzene from 4 M HCl and re-extraction of 0.3 M HCl is recommended for analysis of natural water samples.

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