1. Gas-Phase Reverse Micelles – Generation, Structure and Application
Jianbo Liu, Department of Chemistry and Biochemistry
Queens College and the Graduate Center of the City University of New York, Flushing, NY 11367
We present encapsulation of various amino acids into gas-phase multiply-charged sodium bis(2-ethylhexyl) sulfosuccinate (NaAOT) reverse micelles (RMs). Hydrophilic amino acids are encapsulated into the micellar core through electrostatic interactions; while hydrophobic amino acids adopt zwitterionic structures, and are incorporated at the interface through a combination of electrostatic and hydrophobic interactions. We demonstrate that gas-phase RMs can act as “nanometer-sized vehicles” for selective encapsulation and transport of amino acids from solution to the gas phase.
Preferential encapsulation of Trp over Asp
Collision Induced Dissociation (CID) of amino acid-encapsulating RMs: a) Exclusion of protonated Trp (WH) upon CID resulted in collapse of micellar structure, proving WH was hosted inside the core; b) CID stripped neutral Trp (W) and only W off micelles, proving W was attached to the interface.
Top) Mass Spectrum of solution containing NaAOT and Asp, showing encapsulation of protonated Asp in gas-phase RMs; bottom) After adding Trp to the solution, all Asp signals vanished; instead, only protonated Trp was encapsulated, demonstrating the selectivity of gas-phase RMs.