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. Anti mony 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 am monium 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. Stand ard deviations computed for these analyses also were small. A rapid and safe method for digesting cloth samples with sulfuric and perchloric acids is described.