Column packings monomeric

Sander and wise have proposed a test method to determine the bonding chemistry used to prepare octadecylsiloxane column packings based on the relative retention of three polycyclic aromatic hydrocarbons, benzo[a]pyrene (BaP), phenanthro-phenanthrene (PhPh), and l,2 3,4 5,6 7,8-tetrabenzonaphthalene (TBN) eluted with the mobile phase acetonitrile-water (85 15) [52,67,199,210]. On monomeric phases the test solutes elute in the... 

Monomeric isoprene is purified as described for styrene in Example 3-1 before use it is run under nitrogen through a 30-cm column packed with neutral aluminum oxide cyclohexane and 1,2-dimethoxyethane are refluxed over sodium for 6 h and distilled off under nitrogen. 

Monomeric styrene is destabilized as in Example 3-1 and pre-dried with calcium chlo-ride.The monomer is now allowed to stand over calcium hydride for 24 h and then distilled under reduced pressure of nitrogen into a previously flamed-out Schlenk tube. Pure 4-vinylpyridine is distilled twice over KOH pellets in vacuum.lt is then vacuum distilled under nitrogen through a column packed with Raschig rings into a previously flamed out Schlenk tube (bp 62 °C/12 torr).The closed Schlenk tubes containing the monomers are stored in a refrigerator until required.The preparation of the initiator solution (sodium naphthalene) is described in Example 3-19. 

The so-called Driscoll methods are all based around ion-exchange separation of the monomeric inorganic aluminium from the monomeric organic aluminium. The column packing is Amberlite IR-120 cation exchange resin [159]. In essence, the Driscoll method directly measures three operationally defined fractions ... 

A column (250 x 4.6 mm) packed with a reversed-phase C 18 support, coated with trioctylmethyl ammoniumchloride, separated oligo-uridylic acids and discriminated between (Up)89 and (Up)q0, (Fig. 23)83). In such high a region of molar mass, the separation of components differing in only one monomeric unit is remarkable in polymer chromatography in general. 

Early studies on the use of liquid crystals as stationary phases focused on packed columns however as with other gas chromatographic applications, the technology has now almost exclusively shifted to capillary columns. Several reviews outlining the fundamentals and applications of liquid crystal stationary phases in both packed and capillary columns are available [444-449]. Stationary phases can be prepared from either monomeric or side-chain polymeric liquid crystals. Particularly relevant to the latter is the increased use of polysiloxane and poly-arylate backbones for the attachment of... 

---