Celebration of Scholars
NMR Investigation of Micelle Formation by Phenylalanine-Containing Biosurfactants
Name:
Elizabeth Pieroni
Major: Chemistry
Hometown: Crystal Lake
Faculty Sponsor: Kevin Morris
Other Sponsors:
Type of research: SURE
Funding: NSF-RUI grant #1213532
Abstract
Nuclear magnetic resonance spectroscopy (NMR) was used to study micelle formation by the amino acid-based surfactants undecyl-phenylalanine-glycine (und-FG) and undecyl-glycine-phenylalanine (und-GF). Amino acid-based surfactants like und-FG and und-GF are used in the pharmaceutical, food, and cosmetic industries because they are biodegradable, biocompatible, have low toxicity, and are produced using renewable materials. The surfactants’ solubilities in aqueous solution were found to depend on the counterion present in solution. The surfactant und-FG was insoluble in solutions containing sodium counterions, soluble over a small pH range with L-arginine counterions, and soluble over the entire pH range with tetraethylammonium counterions. The surfactant und-GF was soluble from pH 7.5 to 11.5 regardless of the type of counterion present. Critical micelle concentration (CMC) measurements showed that und-FG micelles formed at lower concentrations when L-arginine cations were present in solution. CMC’s for the und-GF micelles were also generally higher than corresponding und-FG values. The CMC results provide strong evidence that the pH of a solution and the micelle counterion have a direct effect on micellization.Submit date: March 24, 2019, 10:07 p.m.