The best way for removing unreacted SATA (Cat. No 26102) would be HPLC. Another possibility would be to use desalting columns. In case the peptide is bigger than 1.8 kDa, you would like to use the Pierce Polyacrylamide Desalting Columns, 1.8K MWCO, 5 mL (Cat. No 43426).
Find additional tips, troubleshooting help, and resources within our Protein Dialysis, Desalting, and Concentration Support Center.