Final answer:
To separate the trypsin-digested products of the octapeptide AVGWRVKS, ion-exchange chromatography should be used, as it separates molecules based on charge differences and is suited for peptides with varying charges.
Step-by-step explanation:
To separate the digestion products of the octapeptide AVGWRVKS if cleaved by trypsin, one would typically use ion-exchange chromatography. Trypsin specifically cleaves at the carboxyl side of lysine and arginine residues except when followed by proline. Since this digestion generates peptides with different charges, ion-exchange chromatography is an appropriate technique because it separates molecules based on charge differences. Techniques like gel-filtration chromatography, dialysis, and salting out would not provide the specificity needed to separate the digest based on charge properties.
Other relevant laboratory techniques have been applied to peptide digests for protein analysis such as desalting with reverse-phase solid-phase extraction and proteomic analysis by mass spectrometry after in-gel trypsin digestion. The peptides are usually eluted with acetonitrile and trifluoroacetic acid (TFA) before being dried under a vacuum for mass spectrometry analysis.