Stain Protocol for the Detection of N-Terminal Amino Groups during Solid-Phase Peptide Synthesis.

A novel and reversible detection method for N-terminal amino groups and alternative to the Kaiser test during Fmoc-SPPS has been developed. The utility of the new method was exemplified in its monitoring of the construction of a peptide, the final yield of which was higher than that of an identical peptide constructed under identical conditions but using the Kaiser test, and its scope was established to include all 20 proteinogenic amino acids as well as nonproteinogenic ones.