The adsorption kinetics of hydroxyethylcellulose (HEC) on silica and relaxations in adsorbed HEC layers were probed using total internal reflectance fluorescence and near-Brewster reflectivity. Like many random-coil polymers, HEC was found to adsorb at the transport-limited rate. Relaxations occurred at nearly constant interfacial mass when HEC layers were exposed to aqueous solvent, causing th...

We report separations of RNA molecules (281-6583 nucleotides) by capillary electrophoresis in dilute and semidilute solutions of aqueous hydroxyethylcellulose (HEC) ether in varying buffers. RNA mobility and peak band widths are examined under both nondenaturing and also denaturing conditions. From studies of sieving polymer concentration and chain length, it is found that good separations can ...

Anionic capillary isotachophoresis (cITP) with conductometric detection was used for indirect determination of neomycin trisulphate (NMS) as sulphate anion. The following electroylets were tested: leading (LE)--8 mM HCl adjusted with beta-alanine to pH = 3.55, 3 mM bis-tris-propane and 0.2% hydroxyethylcellulose and terminating (TE): 5 mM citric acid; 5 mM formic acid and 5 mM caproic acid. The...

Capillary electrophoresis of lambda double-stranded (ds) DNA (48.5 kbp) in dilute hydroxyethylcellulose (HEC) solutions shows band spreading that cannot be explained by diffusion alone. Dispersion and asymmetry factors of lambda ds-DNA bands were measured as functions of capillary length, HEC concentration and field strength. Band spreading and asymmetry can be explained by a recently developed...

Water-cast films of two ethers of cellulose, hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC), with dispersed silica particles, were deposited on flat substrates. X-ray specular reflectivity was used to characterize the structure of these solid ca. 1000 Å thick films as a function of the added colloidal fraction. It was shown that the structural changes resulting from increasing amo...