We have prepared polyethylene glycol (PEG)-type, polymer-based monolithic columns (PEG-type columns) to study the basic properties of PEG-type monolithic polymers. Chromatographic characteristics of the PEG-type columns were obtained using a semi-micro HPLC system while polycyclic aromatic hydrocarbons and benzene derivatives having various functional groups were utilized as solutes. Results we...

Bench scale column studies were used to examine the partitioning of microorganisms between groundwater and a geologic medium and to examine the effect of hydrogeology (i.e., porous- versus fracture-flow) on organism partitioning. Replicated columns were constructed with intact basalt core segments that contained natural fractures and with the same basalt crushed into particles. The columns were...

The advent of Waters UltraPerformance LC® (UPLC®) technology has enabled chromatographic separations to be routinely performed on columns packed with sub-2 μm particles at high linear velocity. Such separations result in high resolution, excellent throughput, and high sensitivity chromatographic analyses.1-2 These analytical qualities ensure the separation of coeluting metabolites and minimize ...

This review summarizes applications of CEC for the analysis of proteins and peptides. This "hybrid" technique is useful for the analysis of a broad spectrum of proteins and peptides and is a complementary approach to liquid chromatographic and capillary electrophoretic analysis. All modes of CEC are described--granular packed columns, monolithic stationary phases as well as open-tubular CEC. At...

Based on an extended model of Marangoni convection during absorption accompanied by chemical reaction certain characteristics of the process are studied. Thus, the probability of oscillatory modes occurring in the system is analysed, the dimensions of the convective cells are evaluated and the gas-liquid contact time necessary for the instability to appear is determined. The quantitative conclu...

Computational fluid dynamics (CFD) has been applied to investigate the flow field which develops above the vapor feed in packed separation columns. The uniformity of the flow below the packing is assessed by means of the coefficient of variation Kp. The resulting Kp for the standard inlet is input into an empirical correlation depending on the three most important, basically geometrical, dimens...

The title compound, C(13)H(16)O(2), is a chiral bicyclic structure composed of two fused cyclo-hexa-ne rings possessing both boat and chair conformations. The mol-ecules are packed in enantio-pure columns which are pairwise linked forming an overall racemic solid; within the column pairs the packing is governed by weak dipole-dipole inter-actions stemming from stacked carbonyl functionalities (...

A generalized model has been developed for the prediction of pressure drop and flooding in packed columns in which gas and liquid flow countercurrently. The model has been validated for a wide variety of packings, both random and structured. A single mathematical expression is used to describe all flow regimes: dry gas, irrigated gas flow below the load point, loading region, and flooding. The ...

In the title compound, C(6)H(6)Cl(2)N(2), intra-molecular N-H⋯Cl and C-H⋯Cl contacts generate five-membered rings, producing S(5) ring motifs. Pairs of inter-molecular N-H⋯N hydrogen bonds link neighbouring mol-ecules into dimers with R(2) (2)(8) ring motifs. In the crystal structure, these dimers are connected by N-H⋯Cl inter-actions and are packed into columns.