Which of the following techniques is NOT typically used for identifying peptides?

NMR spectroscopy, while a powerful technique for determining the structure of proteins and other biomolecules in solution, is not typically used for the identification of peptides. Instead, it is often employed for studying the conformation and interactions of proteins at the atomic level. It provides information about the molecular environment and can elucidate details about the structure of peptides, but it does not directly provide a method for identification like the other techniques listed.

Edman degradation is a conventional method specifically designed for sequencing amino acids in a peptide. Mass spectrometry is widely used for peptide identification due to its ability to analyze the mass-to-charge ratio of ions, allowing for the determination of the peptide's molecular weight and sequence information. Immunoblotting is utilized to detect specific peptides or proteins through the use of antibodies, making it a practical method for identifying proteins based on antigen-antibody interactions. Thus, while NMR can provide valuable structural information, it lacks the direct applicability for identifying peptides that the other techniques have.