Quantitative Determination of Copper in Natural Rubber

1953 ◽  
Vol 26 (1) ◽  
pp. 251-256 ◽  
Author(s):  
Lewis T. Milliken
Keyword(s):  
Carbon Tetrachloride ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
Oxidation Process ◽  
Aqueous Suspension ◽  
Wet Oxidation ◽  
Acid Extract ◽  
Organic Solution ◽  
Determination Of Copper

Abstract A procedure is recommended in which small amounts of copper in rubber can be measured quantitatively by determining the depth of color of a copper carbamate complex in a carbon tetrachloride solution. The complex is formed in an alkaline solution prepared from an acid extract of the rubber ashed at 550° C. This procedure yields results which are as reliable as those obtained by the more tedious and time-consuming procedures involving the wet-oxidation process which are at present recommended by standardizing organizations. The use of an organic solution rather than an aqueous suspension gives better reproducibility, permits easier use of a photometer, and reduces the interference due to iron by a factor of ten.

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

Collaborative Study Using a ZDBT Colorimetric Method for the Determination of Copper in Alcoholic Products

1967 ◽  
Vol 50 (2) ◽  
pp. 334-338
Author(s):  
Duane H Strunk ◽  
A A Andreasen
Keyword(s):  
Sulfuric Acid ◽  
Carbon Tetrachloride ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Good Precision ◽  
Determination Of Copper

Abstract Results are given on a collaborative study in which a zinc dibenzyldithiocarbamate (ZDBT) colorimetric method is used to measure copper in alcoholic products such as high wine, spirits, gin, whisky, brandy, rum, and wine. In this method, the sample is made ca 0.SN with sulfuric acid, and carbon tetrachloride containing 0.2% ZDBT is added. The colored copper-ZDBT complex is extracted in the carbon tetrachloride and measured at 438 mμ against a similar carbon tetrachloride extract of a blank. Data show good precision, and it is recommended that the ZDBT method be adopted as official, first action.

Serum Copper and Iron on a Single Sample

1958 ◽  
Vol 4 (1) ◽  
pp. 43-48 ◽  
Author(s):  
B Zak ◽  
N Ressler
Keyword(s):  
Quantitative Determination ◽  
Serum Sample ◽  
Organic Material ◽  
Serum Copper ◽  
Inorganic Salts ◽  
Organic Extract ◽  
Phenanthroline Complex ◽  
Extract Phase ◽  
Determination Of Copper

Abstract A procedure has been described for the quantitative determination of copper and iron in one serum sample. The sera are wet ashed to destroy organic material, leaving inorganic salts available in the residue for the subsequent spectrophotometric determination of iron as the ferrous-1,10-phenanthroline complex in the aqueous phase, and copper as the cuprous-2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline in an organic extract phase.

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