Buffer reservoirs

Figure 9.7 Schematic illustration of the flow-gating interface. A channeled Teflon gasket was sandwiched between two stainless steel plates to allow for flow into the electrophoresis capillary, either from the flush buffer reservoir or from the LC microcolumn during an electiokinetic injection.

Two high-voltage power supplies are used to drive the separation. The first power supply applies high voltage through a platinum electrode to the injection buffer reservoir for the first dimension separation. The second power supply applies potential to the interface through its buffer reservoir. The sheath flow cuvette is held at ground potential. 

Traditional electrophoresis paper, cellulose acetate or polymeric gels used as a supporting medium for the electrolyte solution enclosed tank with electrodes and buffer reservoirs dc power supply. 

For electrophoresis, the paper or gel is saturated with the required buffer at the desired pH. The ends of the paper or gel are placed in a buffer reservoir that contains the buffer with which the paper or gel is saturated and that also have electrodes connecting one end to the positive DC terminal and the other... 

A schematic representation of a CE system is presented in Figure 9.1. In this diagram, the CE components have obvious counterparts to those found in slab gel electrophoresis. Instead of buffer tanks there are two small buffer reservoirs, and the capillary takes the place of the gel (or more accurately, a gel lane). The capillary is immersed in the electrolyte-filled reservoirs, which also make contact with the electrodes connected to a high-voltage power supply. A new feature to the conventional gel electrophoresis format is the presence of an online detection system. 

Figure 3 (A) Robot system for lipofection screening (A) Worktable with racks for microplates, buffer reservoirs, plastic, and glass vials. (B) Four tip liquid handling arm. (C) Gripper for transport of microplates and glass test tubes. (D) High power water bath sonicator. ( ) Nitrogen evaporator. (F) Microplate washer. (G) Absorbance reader. (H) Luminescence reader. (/) Transparent hood. (/) CO2 incubator with pneumatic door (from the rear, front view in B). (B) Self-constructed robotic conveyor for the transport of cell culture plates from the incubator to the worktable.

Electrokinetic injection involves using voltage to inject sample onto the capillary. The sample serves as a buffer reservoir (Figure 1). A voltage is applied and the analyte(s) migrate onto the capillary. The amount of material injected is dependent on the mobility of the analyte(s). The quantity injected is given by... 

Print buffers 3X SSC, 3X SSC + 50% DMSO, and 3X SSC + 1.5 M betaine were evaluated at 40, 60, and 80% RH for spot intensity, spot diameter, intraspot variation, and CV (Figure 4.35). The reductions in quill drop volumes and droplet drying times were measured by video microscope and the quill reservoir volume changes determined by weight. In summary, "Solvent evaporation from the print buffer reservoir is the major factor responsible for the variations in the transfer of fluid to fhe slide surface."... 

Figure 13.2 Illustration of the various types of injection methods for lab-on-a-chip applications (a) floating, (b) direct, (c) pinched, and (d) gated. The labeled positions are as follows for panels (a), (b), and (c) reservoir 1 is for buffer, reservoir 2 for sample, reservoir 3 for sample waste, and reservoir 4 is for buffer waste. For panel (d), reservoir 1 is for sample and reservoir 2 is for buffer.

Figure 13.6 Schematic diagram of the dual-end injection CE microchip system with the movable conductivity detector for simultaneous measurements of explosive-related anions and cations, (a) injection mode and (b) separation mode. (a,e) Running buffer reservoirs, (b,d) unused reservoirs, (c, f) sample reservoirs, (g) injected cation plug, (h) injected anion plug, (i) movable contactless conductivity detector, (j—1) cations 1-3, (m-o) anions 1-3. (Reprinted in part with permission from [33]. Copyright 2003 Wiley Interscience.)...

The unintended negative effects of high buffer-salt concentrations on the efficiency of the electrospray can be significantly reduced by adding an appropriate sheath liquid, thus usually improving the spray stability. However, since the sheath liquid acts as the terminal buffer reservoir, it must contain an electrolyte in order to maintain an efficient electrophoretic separation. Therefore, any choice of sheath flow composition represents a compromise between separation efficiency and spray stability. 

Another problem, the potential increase in background noise due to the addition of solvents and modifiers from the sheath liquid (e.g., volatile salts, acids, and bases), has been studied (19). Moreover, because of the different composition of the initial CE buffer reservoir and the sheath liquid, discontinuous and irreproducible conditions may result. These effects can potentially change migration times or even the migration order of the analytes (20). 

Figure8-1. Schematic plot of a linearly arranged multicomponent (k = 1,2multiphase (a,)3,. ..) system with a prefixed chemical potential difference across it. = buffer reservoirs.

A plastic comb inserted into the top of the slab gel during polymerization forms indentations in the gel that serve as sample wells. Up to 20 sample wells may be formed. After polymerization, the comb is carefiilly removed and the wells are rinsed thoroughly with buffer to remove salts and any unpolymerized acrylamide. The gel plate is clamped into place between two buffer reservoirs, a sample is loaded into each well, and voltage is applied. For visualization, die slab is removed and stained with an appropriate dye. 

Once the column is packed (gel bed just runs dry), connect the top of the column to a buffer reservoir, remove any air bubbles in the tube, and allow one column volume of buffer to run through the column. 

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