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

Abstract

A survey has been made of methods available for the spectrophotometric determina tion of copper in fabrics treated with copper-containing fungicides. Seven of the most promising copper reagents were compared on the basis of sensitivity, simplicity of pro cedure, and specificity for copper in the presence of the metallic oxides used to render fabrics resistant to fire, ultraviolet light, and water. Methods employing rubeanic acid and zinc dibenzyldithiocarbamate offered the best combination of desirable character istics. These methods proved to be as precise as the electrolytic method described in current federal specifications. These methods were also successfully tested against commercially treated fabrics obtained through actual Army procurements. Since only 3-5 mg of fabric are required for each determination, these spectrophoto metric methods offer a means of determining the evenness of application of the fungicide on the fabric. The analysis of commercial fabrics treated with copper 8-quinolinolate and copper naphthenate indicated that the textile manufacturing industry is capable of obtaining a very even distribution of this mixture of fungicides throughout the material. Details of the rubeanic acid and zinc dibenzyldithiocarbamate methods are presented.