Radial chromatography

In circular chromatography (radial chromatography), the sample for separation is spotted in the center of a plate as a circular spot. The mobile phase is introduced in the center of the circular chromatographic plate (Rg. 1). This technique can be used with normal chromatographic plates too, but cannot be used with multi-channel plates. 

Most immunoassay kits and many commercial immunoassay analyzers are based on heterogenous EIA or FIA. These include an immunoassay system that uses FIA linked to radial partition chromatography of the antibody—antigen complex (39) a system that uses antibody-coated tubes for enzyme immunoassay of a variety of hormones and dmgs (40) and a system that uses either a sandwich or competitive FIA format to measure a variety of analytes (41). 

R,5S,6R)-4-(t-Butoxycarbonyl)-5,6-dlphenyl-3>[(sthoxycarbonyt)methyl]-2,3,5,6-tetrahydro-4H-oxazln-2-one (6) To a stirred solution of erode 4 (226 mg 0 48 mmoQ m CH2CI2 (11 mL) was added ketene acetal 5 (450 mg, 2 42 mmol) followed by addition of 2nCl2 (575 mL, 0 44 mmol, 0 76M m THF) Alter 4 min ( was quenched with water Radial chromatography (silica gel EtOAc hexane 1 4) afforded 179 mg of 6 (78%)... 

Alternative Chromatographic Columns Commercial radial-flow chromatography (RFC) columns first appeared in the mid-1980s. RFC is an alternative to the conventional axial-flow chromatography for preparative- and large-scale applications. In a RFC column, the mobile phase flows in the radial direction rather than the axial direction. Computer simulation proves that RFC is somewhat equivalent to a pancakelike axial-flow column [Gu, in Flickinger and Drew (eds.). 

If the position of sample application and the point of entry of the mobile phase are at the center of the plate and the flow of mobile phase is towards the periphery of the plate, then this node of development is called circular chromatography [6,110]. Samples can be injected into the mobile phase, in which case they will be separated as a series of concentric rings. If the samples are applied as a cluster of spots in a radial pattern around the solvent entry position, after development, spots near the origin remain symmetrical and compact trtiile those near the solvent front are compressed in the direction of development and elongated at right angles to this direction. Figure 7.10(A). 

Saxena, V., Subramanian, K., Saxena, S., and Dunn, M., Production-scale radial flow chromatography, Biopharmacology, 36, 46, 1989. 

Weaver, K., Chen, D., Walton, L., Elwell, L., and Ray, R, Uridine phosphorylase purified from total crude extracts of E. coli using Q Sepharose and radial-flow chromatography, Biopharmacology, 37, 25, 1990. 

McCartney, J. E., Rapid purification of a recombinant protein using tandem radial flow ion-exchange column chromatography, BioTechniques, 11,648,1991. 

New designs for axial flow process chromatography columns have been examined using ovalbumin separation on Whatman Express-Ion Exchanger Q with a 16 L Side-Pack and a 24 L IsoPak column.38 The Side-Pak column is packed in the transverse direction, so radial inhomogeneity is minimized. 

Dapremont, O., Cox, G.B., Martin, M., Hilaireau, P., and Colin, H., Effect of radial gradient of temperature on the performance of large-diameter high-performance liquid chromatography columns I. Analytical conditions,. Chromatogr. A, 796, 81, 1998. 

Turner and Warnock [56] determined miconazole in human saliva using high performance liquid chromatography. Deproteinated human saliva samples containing miconazole was chromatographed on a C8 reversed-phase radial compression column using 77% methanol in 0.01 M EDTA with 0.005 M w-nonylamine at a flow... 

Additional details of planar chromatography—methods of descending and radial development, how to prepare TLC plates, tips on how to apply the sample, what to do if the spots are not visible—and the details of preparatory TLC, etc., are beyond our scope. 

Continuity and rate equations can also be written in a cylindrical coordinate system for the two-dimensional annular chromatography. Assuming steady state and neglecting velocity and concentration variations in the radial direction, the above-mentioned equations may then be written as... 

The submitters used silica gel (mesh 100-200, BW-820 MH) from Fuji Davison Chemical, Ltd. (Japan). The checkers used radial chromatography (silica gel 60 PF 254 with gypsum, EM Science) with hexane/ethyl acetate (4/1) as eluent for small scale reactions. The checkers used flash chromatography (240 g of silica gel, grade 633, 47 x 61 microns, Davison Chemical) with hexane (1.5 L), hexane/ether (10/1,1.5 L), and ether (1.5 L) as eluent for large scale reactions (100 mmol). 

The verbenone is clear on distillation but yellows slightly on exposure to air. This does not affect its quality. Radial chromatography (4-mm plate, 10% ethyl acetate/hexane) of a 1-g sample yielded 900 mg of pure verbenone, [a]o 222.0° (EtOH, c2.00). Column chromatography (200 g of silica, 10% ethyl acetate hexane)... 

Rate equation analyses for classical size exclusion chromatography have been based on treating the porous matrix as a homogeneous, spherical medium within which radial diffusion of the macromolecular solute takes place (e.g. (28,30,31)) or If mobile phase lateral dispersion Is considered Important, a two dimensional channel has been used as a model for the bed (32). In either case, however, no treatment of the effects to be expected with charged Brownian solute particles has been presented. As a... 

Alkynylphenyl tellurides from arylteUurolates and alkynyliodonium salts (general procedure) To a stirred solution of PhLi in Et20/cyclohexane at room temperature under N2, tellurium powder was added and the solution was stirred for 1 h. The appropriate iodonium triflate was added and the solution was stirred for 2 h. The product was eluted through a small portion of silica gel with CHjCN and the volume was reduced in vacuo followed by purification via radial chromatography. 

---