銅電解液中の微量チオ尿素の定量法について

抄録

For the purpose of investigating some behavior of thiourea in the copper electrolysis, quantitative microanalysis of thiourea in the electrolyte was confirmed by improving the method offered by previous workers which was based on the fact that two molecules of thiourea react exactly with one molecular iodine according to the following chemical reaction.
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A known amount of iodine was added excessively to the electrolyte containing thiourea and the excess quantity of iodine was measured photometrically after extraction with toluene or after reaction with starch. The photometric measurements were determined to be made at 500mμ and 520mμ of wave lengths in the cases of toluene and starch, respectively.
The influences of temperature, pH, and the concentrations of iodine solution at each step of the analytical procedure were examined.
The method of preventing thiourea from oxidation and the treatment of removing such reducing substances as As³⁺, Fe²⁺ and Sn²⁺ from electrolyte were also discussed.