Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Column Packing Modification

the target compound to be bound to the column must be identified, isolated, and activated. In some cases, the column packing is purchased already activated. Once the target is chemically bound to the column, the packing must be slurry packed into the column. Fortunately, these columns concentrate and bind the substrate so they can be broad and narrow like an ideal ion exchange column and are fairly easily packed. [Pg.102]

Zirconium columns kits for preparing affinity columns have been recently released by ZirChrom. They contain an activated linker that can be reacted with the target compound in the prepacked column to prepare the affinity column in situ. Generally, when an affinity column is made, the column must be dedicated to only that one separation. If you have six different affinity separations to make, you must buy six columns. But with these zirconium column kits, the affinity head can be stripped off in the column, the column cleaned, the linker reactivated, and a new affinity column created with a new affinity target without unpacking and repacking the column. This should open create new interest in affinity separations. [Pg.102]


The proper volume of acetylene is measured with a water gasometer as described in Ovg. Synth., Colleat. Vol. 1 1941, 230, with two modifications (a) Two traps immersed in an acetone-dry ice bath at -65°C are placed between the acetylene tank and the gasometer in order to remove acetone. (b) The washing bottles between the gasometer and the reaction flask are replaced by a drying tube (2 x 30-cm column packed with anhydrous CaCl2). [Pg.5]

The modification of the sand surface allows the grains to simultaneously adsorb soluble heavy metals and remove particulate metals by filtration in a column packed with the media. Important factors to the performance of the adsorbent include pH of the solution to be treated, empty bed detention time (EBDT), and the presence of complexing agents, oil, surfactant, and biodegradable substances. [Pg.1101]

In 1957 Golay published his ideas for using columns that were not packed but were open tubes.2 These tubes had to have small inside diameters so they became known as capillary columns, but the name open tubular (OT) columns is more descriptive and preferred. These two types of column necessitate slightly different chromatographic instruments, but the discussion that follows will attempt to integrate them together for simplicity of presentation. In the United States, packed columns were much more widely used than OT columns until recently consequently many laboratories have packed column instruments that, since they will not accept OT columns without modification, are still in use even though OT columns would be preferable for many of their separations. Conversion kits and columns with characteristics intermediate between the two extremes are currently popular. [Pg.63]

Modification of this procedure was applied to the analysis of neutral and amino sugars in mucins [440]. A mixture of 0.2% of ethylene glycol succinate, 0.2% of ethylene glycol adipate and 1.4% of silicone XE-60 was used as the stationary phase and the analysis was effected with temperature programming at l°C/min from 150 to 205°C. Similar results could be obtained, however, on a column packed with 3% of OV-225. Partially ethylated alditol acetates were used to determine the components of polysaccharides [441],... [Pg.172]

Titanium was analysed in a mixture of oxides by Sievers et al. [605]. The tetrachloride was produced by reaction with tetrachloromethane at increased temperature. The reagents were sealed in a small capillary, heated, and the capillary was crushed in a modifed injection port of the chromatograph. A stainless-steel column packed with 15% of Histowax on Gas Pak F at 77°C was used. The analysis of standard samples led to a relative error of 1.1%. [Pg.192]

Determine the column diameter. The generally accepted design procedures for sizing randomly packed columns are modifications of the Sherwood correlation. A widely applied version is that developed by the Norton Company. It has been adapted slightly for this text to permit its application to low-pressure systems. [Pg.369]

Another modification of the LC LC-MS approach is the use of ultra-high-efficiency RPLC columns [54-55]. The system consists of a 800x0.32-pm-lD SCX column (packed with 3-pm polysulfoethyl aspartamide-bonded silica), a 40-nunx75-pm-ID RPLC trapping column, and a 800-nunx30-pm-lD RPLC colunm. The system was applied to the identification of proteins in the proteome of Deinococcus radiodurans [54], and of human plasma proteins [55]. In that case, more than 800 proteins, i.e., both low-abundance cytokines and high-abundance proteins, were identified from in total 365 pg plasma. [Pg.501]

YMC Inc. has simplified the process of scaling up an analytical separation for preparative isolation by developing matched R D column sets. Each R D column set contains an analytical methods development column and a preparative isolation column packed from the same lot of packing material. This provides assurance that any separation developed on the analytical column will scale-up directly on the matched preparative column without further method modification. The use of these column sets eliminates potential selectivity differences caused by different types of silica and different particle and pore size packings by providing matched columns. [Pg.125]

As we will see in Chapter 20, capillary columns are the most widely used in gas chromatography because of their high efficiency due to large numbers of plates. These columns have no packing, and so the eddy diffusion term in the van Deempter equation disappears. For open tubular columns, the modification of the van Deempter equation, called the Golay equation, applies ... [Pg.565]

The sensitivity of flame AAS is insufficient for the determination of cadmium in urine at nonnal levels. ETAAS methods require sample digestion and/or chemical modification of the sample matrix, resulting in complicated procedures. In this procedure, cadmium is determined efficiently by flame AAS in undigested urine following an on-line separation of the matrix and preconcentration of the analyte using a micro-column packed with CPG- 8HQ ion-exchanger (quinolin-8-ol immobilized on porous glass). [Pg.236]


See other pages where Column Packing Modification is mentioned: [Pg.102]    [Pg.102]    [Pg.13]    [Pg.297]    [Pg.175]    [Pg.226]    [Pg.175]    [Pg.259]    [Pg.28]    [Pg.60]    [Pg.626]    [Pg.655]    [Pg.98]    [Pg.132]    [Pg.227]    [Pg.23]    [Pg.217]    [Pg.163]    [Pg.227]    [Pg.22]    [Pg.143]    [Pg.86]    [Pg.878]    [Pg.702]    [Pg.4]    [Pg.266]    [Pg.148]    [Pg.91]    [Pg.94]    [Pg.768]    [Pg.146]    [Pg.310]    [Pg.155]    [Pg.156]    [Pg.183]    [Pg.271]    [Pg.589]    [Pg.665]    [Pg.207]    [Pg.125]    [Pg.215]   


SEARCH



Packed columns

Packed columns, packing

© 2024 chempedia.info