Sample Preparation Method for Simultaneous Determination of the Content and Molecular Weight of Cationic Polymers in Hair Shampoo by Size-Exclusion Chromatography
Junichi Sugiyama1, Hiroyuki Hanihara1, Kosuke Tanaka1, Akinori Igarashi1 and Masami Fujiwara1
(Received 9 September 2005, Accepted 15 November 2005)
In previous paper, we established an accurate analyzing method by combining a size-exclusion chromatography (SEC) with multi-angle laser light scattering (MALLS) and a refractive index detector (RI) for determining the amount and absolute molecular weight of the cationic cellulose derivative {cellulose, 2-hydroxyethyl 2-[2-hydroxy-3-(trimethylammonio)propoxy]ethyl 2-hydroxy-3-(trimethylammonio)propylether,chloride} (CC), which is the most popular cationic polymer used in hair shampoo. However, an appropriate sample-preparation method for the analysis has not been established due to the lack of separation and dissolution procedures of the CC from the shampoo. In this work, we investigated a sample-preparation method in which the CC is efficiently separated from the shampoo without its molecular deterioration. We found that the CC is clearly solubilized by the SEC mobile phase (0.3 mol/l NaClO4 aqueous solution) as long as the CC is separated from the shampoo, because the tetrahydrofuran insoluble matter is immediately diluted by the mobile phase before drying out. In the SEC measurement, the CC from the model shampoo, the recovery rate and the reproducibility were sufficient. Moreover, no deterioration of the CC through the sample preparation was confirmed from a comparison between the molecular weight of the CC separated from the shampoo and that of the standard CC.
Keywords : extraction; preparation; cationic cellulose derivatives; determination molecular weight; polymer; shampoo; SEC; MALLS.
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