Capillary thermo

Fig. 5.9 Design of the chip-based enzyme ESI-MS assay. MS instrument Ion-trap mass spectrometer (LCQ Deca, Thermo Electron). I Sample components/inhibitors injected by flow injection or eluting from capillary HPLC column. E Infusion pump delivering the enzyme cathepsin B. S infusion pump delivering the substrate Z-FR-AMC. Micro-chip design Vrije Universiteit Amsterdam. Micro-chip production Micronit Microfluidics BV (Enschede, The Netherlands).

Table 17.5 Specifications for capillary GC-IRMS coupling techniques i ing DELTA pliK XL, Thermo Electron, Bremen, Germany [52]...

TWO PHASE FLOW IN CAPILLARY POROUS THERMO-ELASTIC MATERIALS... 

Abstract In this contribution, the coupled flow of liquids and gases in capillary thermoelastic porous materials is investigated by using a continuum mechanical model based on the Theory of Porous Media. The movement of the phases is influenced by the capillarity forces, the relative permeability, the temperature and the given boundary conditions. In the examined porous body, the capillary effect is caused by the intermolecular forces of cohesion and adhesion of the constituents involved. The treatment of the capillary problem, based on thermomechanical investigations, yields the result that the capillarity force is a volume interaction force. Moreover, the friction interaction forces caused by the motion of the constituents are included in the mechanical model. The relative permeability depends on the saturation of the porous body which is considered in the mechanical model. In order to describe the thermo-elastic behaviour, the balance equation of energy for the mixture must be taken into account. The aim of this investigation is to provide with a numerical simulation of the behavior of liquid and gas phases in a thermo-elastic porous body. 

Two Phase Flow in Capillary Porous Thermo-Elastic Materials... 

An ultraviolet-laser based thermo-optical absorbance detector for micrometer capillaries was used by Qi et al. [76] to monitor the separation of a mixture of 13 phenylthiohydantoin-amino acids. A modulated pump laser beam periodically illuminated the capillary at a point near its end. Complex deflection and diffraction effects occur at the capillary-solution interface. Perturbation of the refractive index at this interface changes the intensity of the probe beam that is measured using a small photodiode. 

It should be noted that glass, which is often used as a substrate in inkjet printing experiments, is an insulator. Similarly, although thermo-capillary surface instabilities have been seen to develop in the spreading and evaporation of volatile drops on conductive substrates (silicon and brass), no surface oscillations were observed for those droplets placed on glass. ... 

Guelcher, S A etal, 1998, Thermo-capillary Phenomena and Bubble Coalescence during Electrolytic Gas Evolution. Journal of the Electrochemical Society, 145(6), 1848-1855. 

The MIP is usually prepared as a highly cross-linked, rigid bulk polymer and the polymerisation reaction is initiated by photo- or thermo-labile free radical initiators such as 2,2 -azobis(isobutyronitrile). For molecular imprint-based CEC systems, the introduction of the imprinted polymer into the capillary column has been focused on and several approaches have been developed (see below). The polymerisation process can be performed in between 1 and 24 h. It has been shown that the temperature during the polymerisation process is important. A lower temperature leads to imprinted polymers with higher selectivity [47] or better chromatographic performance [39]. 

Protein Sequencing Using Microreactors and Capillary Electrophoresis with Thermo-optical Absorbance Detection... 

A miniaturized protein and peptide microsequencer consisting of either a fused silica capillary reactor or a microreactor made of Teflon is described. The performance of the miniaturized sequencer was evaluated by sequencing 33 and 27 picomoles of myoglobin that were covalently attached to Sequelon-DITC. The products generated by the sequencer were analyzed using capillary electrophoresis with thermo-optical absorbance detection. This CE system provides reproducible migration time (< 0.4% of RSD) and detection limits of less than 4 fmol. 

A modified API source for a quadrapole MS was deseribed by the group of Chait [18]. The system is based on the Perm souree design. The main differenee is that the transport and desolvation of the ion-solvent elusters is affeeted by means of a heated 203x0.5-mm-lD stainless-steel transfer capillary. Frrrther desolvation is achieved by means of collision activation in the low-presstrre region (ca. 150 Pa) between the capillary exit and the skimmer. The vacuum system is a three-stage vacuum system. This system was commercialized by Finnigan MAT (nowadays Thermo Firmigan). 

Figure 5.9 Source design of the LCD Deca with heated capillary and square-rod quadrupole. Reprinted with courtesy from Thermo Finnigan.

In most API sources from Thermo Finnigan, a heated transfer capillary is used, similar to the device described by Chait etal. [18] (Figure 5.9, Ch. 5.3.4). 

Finally, financial support and technical collaborations have been provided NU in antibody areas by Pharmacia and Upjohn Pharmaceutical Company, through the Animal Health and Drug Metabolism Division (J. Nappier and G. Fate). Additional antibody analysis collaborations have been possible through SmithKline Beecham Pharmaceuticals (D. Nesta and J. Baldoni). These contracts have allowed us to become involved in affinity and immunoaffinity CE areas. Isco Corporation, Thermo Separation Products (Thermo Quest), and Waters Corporation have all donated major instrumentation, materials, and supplies to our efforts in the areas of affinity CE. Colleagues at Supelco, Phase Separations, Ltd., J W Scientific, and Unimicro Technologies have all donated coated or packed capillaries for studies in CE and CEC. We are very appreciative of all these collaborations and technical/financial assistance in developing CE, CIEF, and, most recently, ACE approaches for proteins and antibodies. 

---