Multicolumn chromatography

MD (multistage, multicolumn) chromatography was early discovered to be a powerful tool for separating complex mixtures [8]. Two of the protagonists were J. C. Giddings [9,10] and J. F. K. Huber [11]. MD-LC is based on coupling columns in an online or offline mode, which are operated in an orthogonal... 

Fig. 15.1 Basic arrangements in multidimensional gas chromatography (MDGQ a conventional, b multitrap, c multicolumn...

Continuous processes are more efficient than batch processes, as the use of stationary phase is optimized and the amount of eluent needed for the purification is significantly reduced. The concentration of feed mixture inside the column can be much higher than it is in the case of a batch process. As a consequence, productivity is multiplied by a factor of two to five, less manpower is required, usage of stationary phase is optimized, and the amount of solvent used is reduced by a factor of two to ten. Two multicolumn continuous chromatography processes have been commercially implemented at commercial scale for pharmaceutical chiral separahons, these being the simulated moving bed (SMB) process and the Varicol process [15-17]. 

V3. Vestergaard, P., Simultaneous multicolumn liquid-liquid and liquid/solid chromatography with a computerised readout system. Clin. Chem. 16, 651-656 (1970). 

Multidimensional (multistage, multicolumn) high-performance liquid chromatography (MD-HPLC) offers the possibility of cutting the elution profiles into consecutive fractions, where these fractions can be treated... 

The level of purity as well as the required amount of compound is generally imposed by the targeted biological evaluation. The crude cleavage product, however, often does not meet the purity requirement. To allow quick parallel purification and structural assessment an increasing amount of apparatus, softwares and techniques are required in laboratories. The most efficient is probably fast LC/MS and its multicolumn evolution that enables purification of hundreds of compounds a day. Similarly, parallel chromatography devices and TLC spotting apparatus can be found on the market. ... 

The suspension of an SPM sample in 100mL of CH2CI2 is sonicated for 15 min and filtered with a membrane that has a 0.1-pm pore size, the filtrate is evaporated, and the residue is resolved in acetonitrile [24]. The concentration of the chemicals in the SPM extracts is determined using a multicolumn high-performance liquid chromatography (HPLC)/spectrofluorometer/computer system. According to EQ = S([PAH]iEFi +. ..+ [PAH] EF ), the chemically derived induction equivalent (EQ) is calculated to standardize the biological effect of the chemical on the EROD capacity of the Flep G2 cells [25]. 

The composition of the input and output streams were analysed by on-line gas chromatography. A multicolumn HP 6890, equipped with thermal conductivity (TCD) and flame ionisation (FID) detectors was used. Organic reactant and selective oxidation products were separated on an HP INNOWAX 30m/ 320(im/ 0,25 rm Polyethylenglicol column and sensed by an FID detector. Total oxidation products were analysed by the TCD detector using CTRl 6 ft X 1/4 in column. 

Fortunately, as the complexity of macromolecules increases, the precision and sophistication of instruments designed for their characterization improve. The analytical and preparative fractionating columns of GPC used in the 1950s are transformed into automatic multicolumn, multi-detector, high-temperature SEC. Similar advance is observed for TREF and CRYSTAF, now fused into CFC. At the same time, new methods are being developed for faster and more precise characterization by means of the multi-detector liquid chromatography, HTLC or HPLC. 

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