The title of the paper: Isolation and characterization of keratin from chicken feathers https://doi.org/10.1063/5.0002792
Here is the method: Keratin was isolated by dissolving 5g of chicken feather in 95 ml sodium hydroxide 1N solutions at 70°C for 3 hrs. Glacial acetic acid was added to neutralize the solution (pH 7) to obtain a solution of 5% w/v concentration. The chicken feather is then heated at 70°C in a water bath to form a gel. Then heated in an oven at 70°C until dry.
My overall question whether the reaction between acetic acid and the chicken feather with 1N sodium hydroxide be affected if I didn't standardized the sodium hydroxide?
And the second one is that .. how did the author ended up with 5% w/v concentration? Does this mean that the precipitated chicken hydrolyzate constitute only 5g of weight and 95 ml of acetic acid is added? I am confuse with how the author obtain a 5% w/v concentration.