You should prepare diluted samples (1:10 or 1:20, depending on the total protein yield) from the stock when the sample concentration is too high.

I would personally use the NanoDrop since you only need to use 1-2uL and if you take triplicate readings it should be pretty accurate. You can also check the A260/280 value for an idea of nucleic acid contamination.

Dear Satyendra Mondal

Thank you for the reply, I already diluted my protein samples but since it's my first time quantifying this protein, I did it 1:5 diluted, next time I'll go for 1:10 I guess.

Dear Gaurav S. Soman.

Thank you for the reply, I am using Pierce BCA Protein Assay Kit and I did standard dilutions starting from 1mg/ml up to 0.00625 mg/ml but I forgot to include the concentrated standard (2mg/ml) and I diluted my protein samples 1:5, But we moved on with the same concentrations we've got.

thanks for the suggestions!!

Have a nice day

Dear Emma Thompson

Thank you for the reply,

it is good too to use nano-drop but I am still at optimization level that's why I cannot go for nano-drop without BCA or Bradford assays. But I'll put your note in mind for next times! I usually use nano-drop duplicates for RNA.

Have a good day