Silica-based support

The other restriction of SynChropak size exclusion columns is a general one for silica-based supports, that of pH. The most harmful pH is that above 7.5 due to silica dissolution. The bonded phase of SynChropak GPC has some polymeric properties therefore, it is not removed rapidly from the silica at pH 2-3. The bonded phase of SynChropak CATSEC is polymeric and stable at pH 2-7.5. 

Chemical composition of packings. Today, a wider variety of different support materials is available from which to choose. Silica is still widely used, though preparative grades often possess a relatively wide particle size distribution as compared to polymer-based supports. One serious limitation of silica-based supports is the low stability of silicas to alkaline pH conditions, which limits use of caustic solutions in sanitization and depyrogenation. Polymer-based supports, which include poly(styrene-divi-nyl benzene)- or methacrylate-based materials, are widely available and have gained increased acceptance and use. Nonfunctionalized poly(styrene-divinyl... 

Size-exclusion HPLC (SE-HPLC) separates proteins on the basis of size and shape. As most soluble proteins are globular (i.e. roughly spherical in shape), separation is essentially achieved on the basis of molecular mass in most instances. Commonly used SE-HPLC stationary phases include silica-based supports and cross-linked agarose of defined pore size. Size-exclusion systems are most often used to analyse product for the presence of dimers or higher molecular mass aggregates of itself, as well as proteolysed product variants. 

Table 3.1 Solid-phase extraction using polystyrene and silica-based supports.

Bonded-Phase Supports The bonded-phase supports usually overcome plethora of the nagging problems which is mostly encountered with adsorbed-liquid phases. Here the molecules, comprising the stationary phase, i.e., the surfaces of the silica particles, are covalently bonded to a silica-based support particle. 

Norbomene was functionalized with cyclodextrins and surface grafted onto silica-based supports using ROMP (44). The CSP are suitable for the enantioselective separation various amino acids, including jS-blockers and other compounds, such as chiral ferrocene derivates. 

Further studies have shown that the same reagent species can be effectively constructed on a silica backbone giving appreciable increased reactivity151 (S.V. Ley, unpublished results). A silica-based support provides advantages in terms of more effective heating profiles because of the superior absorbency of the silica and increased compatibility with... 

This is a silica-based support (85-90% Si02) containing alumina (3-6%) and can be found in nature in the form of fossilized diatoms. This type of support has found primary usage in both continuous-flow oligonucleotide and peptide synthesis. Typical loadings are in the range of 0.05-0.13 mmol amine/g and go by the names NovaSyn KD (Calbiochem-Novabiochem Corp.) or Macrosorb K (Phase Separations Ltd.) [31],... 

Rapid Separation of Proteins and Peptides using Conventional Silica-Based Supports Identification of 2-D Gel Proteins Following In-Gel Proteolysis... 

Rapid Separations Using Conventional Silica-Based Supports... 

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