(251a) Hydration and Solute Diffusion in Keratin Fibers Using Novel Chromatographic Approach

Hydration and Solute Diffusion in Keratin Fibers using  Novel Chromatographic Approach

N. Ali^*, D.R. Williams^*, J. Marsh ^**

^*Surface Particles Engineering Laboratory, Department of Chemical Engineering

Imperial College, Kensington, London SW7 2BY

^** The Procter & Gamble Company, 11810 East Miami River Road, Cincinnati, Ohio 45252

Abstract

Over the years there has been considerable progress in understanding the structure and properties of hair. However, we still do not fully understand about the structure of hair and the penetration chemistry of actives in the hair.  Hydration of hair, for example, is a fundamental process. It governs swelling behaviour, structure, diffusion rates and mechanical properties of hair. Despite its importance, keratin water interactions are poorly understood. This is particularly true for hydration along single hair fibres and across hairs from different body sites, genders, ethnicities and ages. Addressing these key knowledge gaps will allow us to unlock critical insights to enable innovation.

The technique used for this investigation is Inverse Liquid Chromatography (ILC). ILC is the inverse of a conventional liquid chromatographic technique where, a solvent and solute mixtures of known properties in the mobile phase while the solid, stationary phase is the subject of investigation. ILC technique has previously been used in research to determine isotherms and enthalpies (Ylä-Mäihäniemi, 2007).  However, ILC has never been applied to understand solid liquid interactions in keratin fibres such as hair.  Applying ILC to understand physicochemical properties of hair is, therefore, a novel approach.

For these ILC experiments a conventional High Performance Liquid Chromatography (HPLC) is employed. A glass column fully packed with a standard hair sample serves as the stationary phase. Two main experiments were carried out; elution and frontal analysis. Elution experiment consists of injecting a pulse of various solvents and monitoring the absorbance until all injected mobile phase has emerged.  Based on the affinity of the solutes to the stationary phase, injected molecules will have different retention time in the column, which is analysed to determine specific properties of the stationary phase material.  A frontal analysis experiment involved running two different solvents alternately and investigating the adsorption and desorption processes of these solvents from the surface of the hair. Preliminary data showing aqueous solute diffusion behaviour within hair using these chromatographic methods will be reported.

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