Separation of nonionic compounds by electrokinetic chromatography using an inorganic layered compound as a pseudostationary phase.
The use of an inorganic layered compound as a pseudostationary phase (PSP) in EKC was investigated. A synthetic smectite, which is the most typical swellable clay mineral, with an average diameter of 130 nm was selected as the PSP. The retention characteristics of the smectite and on-line sample concentration by sweeping were examined for the analysis of polyoxyethylene mono phenyl ethers (PPEs) with different degrees of ethoxylation. The retention factor was increased with increase in the number of ethylene oxide groups and a good separation of the PPE homologs was achieved by smectite-EKC. The RSD of the migration time, plate number, and peak area were 0.60, 8.3, and 2.7% (n = 5), respectively. The developed method can be applied to the analysis of PPEs in commercially available consumer products without any sample pretreatments. In addition, ca. 100-fold sensitivity enhancements for the PPEs with high retention factors were obtained by sweeping.
Koike
Ryo
R
Analytical Science Research Laboratories, Kao Corporation, Wakayama-shi, Wakayama, Japan. koike.ryo@anchem.mc.kyoto-u.ac.jp
Kitagawa
Fumihiko
F
Otsuka
Koji
K