Electroanalysis with Controlled Cathode Potential of Metallic Copper Applied to Fabrics as Metallo-Organic Fungicides

Abstract

A method is described for the electrolytic determination of copper in fabrics treated with organo-copper fungicides. The samples investigated contained fire retardants as metallic oxides, among which were those of antimony, calcium, zinc, and iron. Antimony offers the greatest interference in the electrolytic determination of copper. This interference was eliminated by depositing the copper from ammonium tartrate solution with careful control of the cathode potential, using a laboratory potentiometer to measure the voltage. Data are presented showing that copper may be electroplated from ammonium tartrate solutions, containing a six-fold greater concentration of antimony, with a cathode potential of — 0.60 volts. Standard deviations for analysis of these solutions were small (± 0.001 mg. Cu/ml.), giving an error term of 0.05% (standard dev. of the mean, σ/mean determination × 100). Results are also given for analyses of fabrics containing copper-8-quinolinolate and copper naphthenate singly or in mixture. Standard deviations computed for these analyses also were small. A rapid and safe method for digesting cloth samples with sulfuric and perchloric acids is described. _

A Critical Comparison of Available Methods for the Spectrophotometric Determination of Micro- Amounts of Copper in Textiles

“…Rubeanic acid provided results which were consistently comparable to the electrolytic results of both Bubernak and Baskin [3] and the military quality control laboratory. The rubeanic acid method is also extremely easy to perform and requires a minimum of triple-distilled water and glassware; hence, it has been selected as the method of choice.…”

“…It was found that the spectrophotometric methods were as precise and specific as the electrolytic method. Fortunately, it was possible to compare the methods directly with samples of the same fabrics which Bubernak and Baskin [3] ] used to establish the standard procedure for the electrolytic determination of copper in textiles.…”