2.3. Molecular weight of feather keratin
The molecular weight of extracted keratin was determined by gel permeation
chromatography. It was carried out on a PerkinElmer Series 200 system at 35 ◦C
(TSKgel PWXL 10 m, 7.8×300 mm column). 0.05 M NaNO3 was used as the eluent
and the flow rate was 0.8 ml/min.