Pipetting parallel

Instruments in which each test is performed in its own container or slide are known as discrete analysers, in contrast to flow analysers in which the samples follow each other through the same system of tubing. All discrete analysers have a common basic design incorporating a pipetting system, a photometric detector and a microprocessor. A development of the single test instrument is the parallel fast analyser, which analyses several samples simultaneously but for only one constituent. However, the change-over from one analytical procedure to another is quick and simple. 

Step 1. Pipette 1.0 mL of strontium carrier into a water sample (maximum volume 1 L). Add 1 mL of 8 M HNOs per 100 mL of sample and mix. Bring to a boil and then cool. Note Process a second, tracer standard, sample in parallel after pipetting l.OmLof90Sr standard solution into the acidified solution. Also process a third, blank, sample in parallel by the procedure below. 

Figure 3 Pipetting tip used for 384-channel parallel multidispensing of low-volume aliquots out of one aspiration. The structure of the liquid column in the tip is shown schematically. TAG stands for Trailing Air Gap . After dispensing of the last aliquot in the plate-replication cycle, each tip is washed from the inside and the outside with DMSO. The piston movement is used to accurately meter the small aliquots being dispensed. The piston also acts as a valve regulating the flow of system liquid through the tip for the DMSO flow-through wash. Washing of the outside of the tip is not shown...

Approximately 100 mg of resin was distributed to each of the reaetion bloek wells (of an ACT block or a Bohdan block) by pipetting a slurry of the resin in DMF/DCM (3 1) or as dry resin into each IRORI kan. The peptides were then assembled by the combinatorial chemistry apparatus suited for parallel or split-and pool-synthesis (34) using in situ neutralization/HBTU activation protocols for BOC chemistry. The resin was initially washed with DCM and the BOC protecting group removed by washing twice with a 40% solution of TFA in DCM. 

Pipetting stations may be used to automate an analytical procedure for which an automated analyzer does not exist or cannot be cost justified. Most pipetting robots are relatively easy to program, rarely malfunction, and can deliver liquids with extreme precision and accuracy. Multiple-channel pipetting robots allow parallel processing of specimens with 8- or 12-channel probes to handle microtiter plates. 

A similar experiment was performed in a 96-well plate format. The components of the polymerization mixture were the same except for the solvent (CH3CN was used instead of CH2C12). The polymerization was thermally initiated. The solutions were dispensed using a pipetting robot (Fig. 7.7) and the supernatants analyzed in series by HPLC-UV or in parallel with a plate reader. Eleven WellMIPs were prepared and screened for each monomer. As seen in Fig. 7.9, the reproducibility of the automated procedure is good and the fast parallel assessment delivers similar results as the serial analysis by HPLC. 

In 1993, DeWitt et al. described the Diversomer apparatus [57-59], which is one of the first reaction apparatus designed exclusively for the parallel synthesis of small molecules. Pipetting machines dispense reagents and solvents into vials that are located in a custom-... 

The execution of the parallel synthesis of up to 96 single compounds by the Multipin method involves pipetting the reactants to each well of a 96-well microtiter plate. The pin array is then placed on top of the plate and the resin is allowed to incubate with the reactants to perform the coupling step. The reaction temperature can be raised to 90°C by placing the reaction block into an incubator. Following each reaction step, the pin array is removed and treated in batch to wash the solid support. These operations are repeated until the desired combinatorial synthesis is completed. The resulting compounds can then be removed from the pins into individual wells on a microtiter plate, each of which ideally contains one single compound. 

From 2 to 3 values from the shallow branch of the B = F(t) curve (i.e., at long intervals) the experimenter estimates the bound ligand at t = °o (i.e., at equilibrium). For the nonspecific binding, a (n + 1) solution is run in parallel with an excess of nonradioactive ligand. This soup recipe yields only one binding value per time point, but this one is exact. If you don t believe this, you are welcome to cook the soup three times. You also save yourself time and pipetting work. A similar procedure also yields the best values for dissociation. If you have fast kinetics or want to get very exact measurements, you can try BIACORE (see Section 2.2.5). 

Combinatorial libraries are prepared by the (1) parallel synthesis of arrays, (2) split-pool method, (3) biological method, or (4) spatially addressable parallel synthesis [74,78-80]. Parallel synthesis is carried out by the simultaneous synthesis of an array of different compounds. Several methods are available. In the multipin method, the peptide synthesis is carried out on polyethylene rods that have attached protected amino acids [81]. The amino acid sequence of a synthesized peptide on a particular pin depends on the order in which the amino acids are added. The number of products synthesized is the same as the number of pins. Another version of parallel synthesis, known as the teabag method, uses resin-filled bags in place of pins [74]. By pooling the resin portions from the appropriate bags, followed by redistribution and further coupling with a specific amino acid, a peptide library can be synthesized. The SPOT method uses a cellulose paper membrane as a solid support, which acts as an open reactor. Respective reagent solutions are pipetted onto several spots to synthesize as many peptides as the spots chosen [74,82]. 

Immediately place the tnbe in a 37°C water bath, hybridization oven, or thermocycler in which the heated lid parallels the block temperature. Incubate for 16h. Periodically mix the components by gentle pipeting and pulse to collect condensation. We generally leave this reaction to run overnight in a 37°C water bath with a sealed lid. 

About 2 cm further away from the tapered shaft, break the tubing with a diamond pen and fire-polish the end to yield an S-shaped holding pipet. When used, the pipette shaft will extend, parallel to the floor of the culture dish, into the microdrop for manipulation (Gordon and Ruddle, 1983). The tubing will then extend vertically up and over the edge of the tissue culture dish, and attach to the instrument collar of the manipulator. 

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