Characterization of colloidal hematite particle shape and dispersion behavior.

An elliptically polarized light scattering (EPLS) technique for the size and shape characterization of ellipsoidal hematite particles is presented. The hematite particles are synthesized by aging aqueous FeCl(3) or Fe(NO(3))(3) solutions at 100 degrees C. Different reaction conditions create particles of aspect ratios between 1 (spherical) and 8 (elongated).

Evaluation of advanced silica packings for the separation of biopolymers by high-performance liquid chromatography. V. Performance of non-porous monodisperse 1.5-microns bonded silicas in the separation of proteins by hydrophobic-interaction chromatography.

Non-porous monodisperse 1.5-microns silicas were allowed to react with (A) and (B) N-acetylaminopropyltriethoxysilane to generate bonded phases useful in high-performance hydrophobic-interaction chromatography (HIC). Differences in the selectivity were observed between the amide and the ether phase.

Evaluation of advanced silica packings for the separation of biopolymers by high-performance liquid chromatography. IV. Mobile phase and surface-mediated effects on recovery of native proteins in gradient elution on non-porous, monodisperse 1.5-microns reversed-phase silicas.

The reversed-phase chromatography of proteins by gradient elution with acidic, low-ionic-strength aqueous-organic eluents is often associated with losses of the biological activity of the protein. In this study, the enzymatic activities of catalase, horseradish peroxidase and pepsin were examined under static and dynamic column conditions on non-porous, monodisperse 1.5-microns reversed-phase silicas with various n-alkyl ligands.

Evaluation of advanced silica packings for the separation of biopolymers by high-performance liquid chromatography. III. Retention and selectivity of proteins and peptides in gradient elution on non-porous monodisperse 1.5-microns reversed-phase silicas.

Following previous studies of the use of non-porous monodisperse 1.5-microns n-octyl- and n-octadecyl-bonded silicas in gradient elution of proteins, this work was aimed at elucidating further the properties of this novel column material for peptide and protein separations in comparison with wide-pore silicas. First, it is demonstrated that with short columns (e.

Optimum support properties for protein separations by high-performance size exclusion chromatography.

Optimum chromatographic properties of high performance size exclusion chromatography (HPSEC) of proteins, such as resolution, molecular weight accuracy and recovery, are obtained on packings and columns with tailor-made physical and chemical structures, employed at properly adjusted eluent compositions and operation conditions. SEC-theory suggests that a broad molecular weight fractionation range and high linearity of the log-linear calibration plot can be achieved by the use of two packings (10- and 80-nm pore size, characterized by a pore-size distribution (psd) equal to or less than 1 decade and by equal internal column porosity (p)), rather than a single 30- to 50-nm pore-size packing with a wide psd. Favourably high-phase ratios of (p)/(o)/ 1.