Down-scaling Sample Preparation Using Polyurethane Foam and Colorimetric Technique for the Chromium Assay in Accessories

A simple alternative colorimetric assay of chromium in accessories is proposed. A miniature part of a sample was dissolved by acid digestion. With dithiooxamide (DTO) complexes, metal interferences are retained in polyurethane foam synthesized in the lab, while chromium ions are present in the eluate. A 100-μL volume of the eluate was measured for the absorbance using a handy spectrometer. The proposed method was successful for chromium assay and the results obtained agreed with the reference (FAAS) method. The amounts of chromium in accessories were found in the range of 100 to 390 mg g^–1.