Search results for "Particle diameter"
showing 4 items of 4 documents
Comparative study of the performance of spherical and angular silica and alumina supports in the 1-10-μm size range
1978
Summary Columns packed with four different sets of well characterized packings, spherical silica, angular silica, spherical alumina and angular alumina, varying in mean particle diameter ( d p ) between 1 and 10 μm, were compared. On these columns, the chromatographic permeability ( K 10 ), the column resistance parameter (Φ) and the reduced plate height-velocity dependences were determined under identical and comparable conditions. Discrepancies were found for K 10 and Φ depending on the type of packing and the particle shape. The courses of the h versus v plot, however, were nearly identical for packings with d p > 4 μm, showing a minimum at v ≅ 5 and h = 1.5–2.5 for solutes of k ′ ≅ 0.2 …
Comparative study of Zorbax Bio Series GF 250 and GF 450 and TSK-Gel 3000 SW and SWXL columns in size-exclusion chromatography of proteins.
1988
Abstract A reduction of the mean particle diameter of silica-based packings in the size-exclusion chromatography (SEC) of proteins to about 5 μm generates the expected increase in column plate number over the traditional 10 μm SEC columns, as demonstrated for the Zorbax Bio Series GF 250 and GF 450 and TSK-Gel 3000 SWXL columns. The slightly lower column efficiency of the TSK-Gel 3000 SWXL compared with the GF 250 column is compensated by the fact that the phase ratio of the 3000 SWXL column is higher by a factor of two. Hence both columns show nearly the same peak capacity of about 20–30. When the ionic strength of the eluent was changed by varying the salt concentration, the elution volum…
Comparison between grain-size analyses using laser diffraction and sedimentation methods
2010
A comparison between laser diffraction method (LDM) and the sieve-hydrometer method (SHM) was carried out for 228 soil samples representing a different texture classification sampled in a Sicilian basin. The analysis demonstrated that the sand content measured by SHM can be assumed equal to that determined by LDM technique, while the clay fraction measured by LDM was lower than that measured by the SHM. A set of equations to transform LDM results to SHM results was proposed. The influence of the LDM measurements of clay on the estimated percentage of silt + very fine sand particles (particle diameter ranging from 0.002 mm to 0.1 mm), which is useful for estimating soil erodibility, was also…
Gelchromatographie. 10. Mitt. Die Optimierung der Analysenzeit
1971
Aus theoretischen uberlegungen folgt, das unter gegebenen experimentellen Bedingungen eine Verkurzung der gelchromatographischen Analysenzeit stets zu einer Verschlechterung des Auflosungsvermogens fuhrt. Kurzere Analysenzeiten bei gegebenem Auflosungsvermogen sind dagegen molich, wenn die Saulenlange und der Partikeldurchmesser des Gels gleichzeitig verringert werden. It can be derived from theory that a reduction of analysis time at fixed experimental conditions results in a deterioration of resolution. Shorter analysis times at constant resolution are possible if column length and particle diameter of the gel are reduced simultaneously.