N ‐Laurylbiotinamide as Affinity Surfactant

N ‐laurylbiotinamide (NLB), which retains strong affinity for the protein avidin, was synthesized from biotin and N ‐laurylamine via the biotin ester of N ‐hydroxysuccinimide and characterized by NMR. When the synthesized NLB was used as a cosurfactant with AOT to form a reverse micellar system in isooctane, it was found to extend the pH range over which avidin can be transferred from a continuous aqueous solution to the reverse‐micellar phase. This behavior is similar to that already reported for a different affinity surfactant, n ‐octyl β‐D‐glucopyranoside.