For centuries, silk has been a highly valued material. To protect historic silk materials, it is necessary to assess the degree of its degradation. This can be observed through the changes in chain lenght of protein fibroin, which is the main component of silk. The molar mass distribution of fibroin can be determined using size exclusion chromatography (SEC). I optimized the silk sample preparation method for SEC analysis and I analyzed different types of silk. I analyzed silks of three different origins (Slovenian, Indian and Belgian), different weighted silks, four different degraded silks and silks treated with trypsin. It turned out that the optimum sample preparation is as follows: samples were dissolved in concentrated LiBr, then dialyzed for 6 h, 1 h in MQ-water and 5 h in the citrate buffer used for the mobile phase and centrifuged at the end. Stability of the samples in LiBr has been investigated and found that the sample decays with time in LiBr. I found that different methods of accelerated degradation of silk had different effects on its degradation, with higher temperature and higher humidity accelerating the process. Silk weighting made its dissolution more difficult, as the weighted silk did not completely dissolve using the selected process. FTIR method analysis was conducted to determine which components of silk remain undissolved and it was revealed that part of the fibroin remained undissolved.
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