Abstract

This study examines the relationship of Cr(VI) formation in leather and wool fibres to the level of Cr and the ironing temperature in double-face processing. The chromium oxide levels in both the leather and wool fibres of the skins were measured. An increase in the amount of basic chromium sulphate used was shown to increase the chromium content in both leather and wool fibres. Related to this increase, parallel increases in the amount of Cr(VI) in leather and wool fibres were detected by the analysis method – DIN 53314 (IUC 18: 1997). Furthermore, higher temperatures during the ironing processes produced higher levels of Cr(VI) in leather and wool fibres.

To eliminate any false-positive results due to the interference of dyestuffs in the Cr(VI) determination with dark coloured extracts, Br2/water solutions were added to extract solutions and the measurements were repeated in the transparent extracts. A comparison of the results revealed that in the extracts with Br2/water addition, Cr(VI) values were lower and it was concluded that Br2/water solution eliminated the dyestuff interference and, therefore the false-positive results.