I'm currently experiencing problems during acid hydrolysis for total amino acid analysis as my first samples contain high amounts of sugar (I get too low results back). I therefore had the idea to precipitate nitrogenous materials (amino acids, protein/peptides) to remove sugars. I found the following method suggested in another question:

1. Reduce pH with TFA

2. Cool to 4*C (Celsius)

3. Add excess of Dimethylether or petroleum ether

4. Centrifuge

Can anyone confirm this is a good idea or does anyone have a better suggestion?