Quaternary amine (Q-type) is the classic strong anion exchanger (fully ionized across the entire working pH range). Hydroxyapatite acts as a mixed-mode crystalline calcium phosphate matrix exhibiting strong phosphate/anion exchange binding. DEAE is a weak anion exchanger, and sulphonate is a strong cation exchanger.

SDS denatures proteins and binds at a constant ratio of approximately $1.4\text{ g SDS/g protein}$, conferring a uniform negative charge density and identical charge-to-mass ratio. Consequently, separation in the polyacrylamide gel occurs exclusively based on molecular size through the molecular sieving effect of the gel pores.

1-Fluoro-2,4-dinitrobenzene (FDNB / Sanger's reagent) and Phenyl isothiocyanate (PITC / Edman's reagent) are standard reagents used for N-terminal amino acid determination. Ninhydrin reacts with all free alpha-amino acids to produce Ruhemann's purple and is not specific for N-terminal sequencing.