Capillary column technology materials

CAPILLARY COLUMN TECHNOLOGY 3.9.1 Capillary Column Materials... 

Several research groups used another interesting column technology as an alternative to the modification of the capillary surface. This method is inherited from the field of electrophoresis of nucleic acids and involves capillaries filled with solutions of linear polymers. In contrast to the monolithic columns that will be discussed later in this review, the preparation of these pseudostationary phases need not be performed within the confines of the capillary. These materials, typically specifically designed copolymers [85-88] and modified den-drimers [89], exist as physically entangled polymer chains that effectively resemble highly swollen, chemically crosslinked gels. 

Column technology is an active area of exploration in CEC for efficient and fast separations. The issues dealt in this section include capillary materials and column types used in CEC. 

Two methods are used for the preparation of capillary gas adsorption columns the suspension method, in which the inner walls of the column are coated with a suspension of the adsorbent, and the chemical method, in which an adsorption layer is formed on the walls of the column through a process of synthesis of the adsorbent in the capillary column. Recently, a new type of porous polymer (poly(l-(trimethylsilyl)-l-propin) (PTMSP)) has been suggested as an organic adsorbent and has been actively studied as a promising material in membrane technology. This polymer dissolves well in some volatile solvents, and a layer of it can be formed in a capillary column using simple techniques for coating from a solution of a stationary phase in a volatile solvent. 

Electrochemical detectors for liquid chromatography have reached a level of maturity in that thousands of these devices are used routinely for a variety of mundane purposes. Nevertheless, the technology is advancing rapidly in several respects. Multiple electrode and voltammetric detectors have been developed for more specialized applications. Small-volume transducers based on carbon fiber electrodes are being explored for capillary and micropacked columns. Recently, electrochemical detection has also been coupled to capillary electrophoresis [47]. Finally, new electrode materials with unique properties are likely to afford improved sensitivity and selectivity for important applications. 

---