Presence of Chromium (VI) in sheepskins: influence of tanney processes

Abstract

In this work, the results of a preliminary study on the influence exerted by neutralization, washing, ageing and vegetable retanning on chromium (VI) content in sheepskins are presented. In neutralization, the presence of chromium (VI) in skins is observed, in a concentration that depends on the pH to which they have been neutralized. However, chromium (VI) practically disappears once the skins have been fatliquored and thoroughly washed. Analysis of skins not retanned and finished exposed to UV light showed a marked increase in chromium (VI)content. By contrast, skins retanned with quebracho withstood the same conditions without noticeable quantitaties of chromium (VI) being detected. Although the analytical results were obtained using the IUC 18 Standard, an alternative procedure based on the capillary electrophoresis technique was developed to verify the results. This method allowed us to confirm the presence of considerable quantities of chromium (VI) in samples subjected to photoageing