A Rapid Method for Measuring Elastin Degradation and Its Application in Leather Manufacturing

Abstract

The degradation of elastin in skins during leather manufacturing can increase the yield area, softness and flatness of the leather, but, excessive degradation of elastin in leather processing induces looseness and increases veininess in the final leather product. However, the characterization of the degradation degree of elastin in skins and leathers was mostly studied through histological analysis qualitatively. There is an urgent need to develop a more efficient quantitative analytical strategy to evaluate the degradation of elastin in leather making processes. In this study, a simple and rapid HPLC method is developed for measuring elastin degradation in skins, leathers and leather processing liquors through determining the biological markers of elastin, namely desmosines. The separation of analytes was conducted on an C₁₈ column (4.6 × 150 mm, 4.0 ?m) at 30 ?; the wavelength of diode array detector (DAD) was set at 275 nm; the mobile phases were composed of methanol and aqueous acetic acid (2.0 %, v/v). A gradient elution was carried out at a flow rate of 0.5 mL/min. It has been witnessed that Cr (III) has no effect on the retention time and peak area of desmosines, when the concentration of Cr (III) was in the range of 0 to 200 mg/L. In quantitative analysis, all of the calibration curves showed good linear regression (R² ? 0.9990) within the tested ranges, and the recovery of desmosines was 100.9 % and 102.6 % for elastin hydrolysate and Cr-tanned elastin hydrolysate, respectively. The content of desmosines in elastin fiber, Cr-tanned elastin fiber and leather manufacturing liquors measured by established HPLC-DAD were comparable to the results obtained by amino acid analyzer. In the wet blue bating process, the quantitative analysis results are consistent with the histological staining results. The results demonstrate that the developed method is accurate and effective and can be readily utilized for the comprehensive process control of leather manufacturing.