Pipets filling

To assess possible adsorption of antisera to the Ventana dispensers, a Ventana pipeter filled with L26 antisera was stored at 4°C for up to 1 mo. At the end of the storage period, the antisera was decanted, and the pipeter thoroughly rinsed with PBS. The pipeter was then stained to assess antibody adsorption using sequential application of standard immunostaining reagents. After 4 wk of storage, there was no detectable immunoreactivity in the Ventana pipeter. 

Simple Filtration by Celite. A disposable pipet filled with celite is fitted with a rubber septum and is placed at the inlet of a Schlenk flask by means of a thermometer holder. Then the whole system is evacuated and filled with inert gas. Transfer of liquid is carried out by the cannula method. The Schlenk receiver should be at ambient pressure, although careful evacuation can accelerate the filtration. 

Two different arrangements were used to probe the transfer of tetra-ethylammonium cation (TEA+) between water and DCE (53). Cell 1 includes a pipet filled with an aqueous solution containing supporting electrolyte (LiCl) and immersed in a DCE solution containing TEA+ ... 

It was shown recently (52) that pipets filled with an organic solvent are suitable for quantitative voltammetric measurements in aqueous media (see also Sec. III.C). Using such a pipet as an SECM tip one can probe IT from organic phase to water and perform imaging in aqueous solutions. The /,... 

Obtain a 10 pL (or lambda) pipet. Fill it with the filtered sample and spot the sample on the pencil dot. 

Insert a small cotton wool plug into a Pasteur pipet, fill to approx 3 cm with anhydrous sodium sulfate, and transfer the sample to the Pasteur pipet. Then force the solution through the bed of anhydrous sodium sulfate with a Pasteur pipet bulb. The conditions for GC/MS are as follows. Injector temperature is 250°C oven temperature is initially 100°C (1 min) and is then increased to 300°C at 10°C/min. 

Using a sterile Pasteur pipet, fill in the sample wells with freshly prepared molten 0.8% agarose. Allow to cool (see Note 22). 

Setting Up Equip the conical vial with a spinvane and add 10 mg of 2-naphtha-lenesulfonic acid and 2.5 mL of toluene. Working at the hood, use two different syringes to measure first 0.35 mL of 3-buten-2-one and then 0.50 mL of 2-methyl-propanal directly into the conical vial. Set up the apparatus for simple distillation. Using a Pasteur pipet, fill the well of the Hickman stillhead with toluene, being careful not to allow any toluene to flow back into the conical vial. 

Fig. 2. Effect of tip size and filling medium on reference electrode tip potentials. Single measurements in NaCl or KCl with reference electrode against a 3 M KCl agar bridge. Left panel, lithium acetate filled electrodes with 1 y m tip, broken tip (40 y m), and 5 y m tip (with and without agar). Right panels, pipets filled with KCl or NaCl with or without agar 2g/100 ml.

The next step in characterizing this electrode system was to define the contribution of sodium in the test solution to the reading of the K electrode. Results of measurements in small drops of solutions with varying potassium and sodium concentration are shown in Fig. 4. The reference electrode for these measurements was connected to a 5 y m pipet filled with 3 M LiAc. The reference potential of this pipet changes more than that of a pipet filled with. 15 M NaCl, but we selected the lithium solution for our initial measurements because the selectivity of the K ion exchanger is about ten times less for lithium than for sodium. The lower line connecting the open circles shows the response in solutions of... 

Pipets and volumetric flasks provide a more accurate means for measuring volume. When filled to its calibration mark, a volumetric flask is designed to contain a specified volume of solution at a stated temperature, usually 20 °C. The actual vol-... 

Second, when filling a pipet or volumetric flask, set the liquid s level exactly at the calibration mark. The liquid s top surface is curved into a meniscus, the bottom of which should be exactly even with the glassware s calibration mark (Figure 2.6). The meniscus should be adjusted with the calibration mark at eye level to avoid parallax errors. If your eye level is above the calibration mark the pipet or volumetric flask will be overfilled. The pipet or volumetric flask will be underfilled if your eye level is below the calibration mark. 

The device most commonly used to measure volume in general chemistry is the graduated cylinder. A pipet or buret (Figure 1.8) is used when greater accuracy is required. A pipet is calibrated to deliver a fixed volume of liquid—for example, 25.00 mL—when filled to the mark and allowed to drain. Variable volumes can be delivered accurately by a buret, perhaps to 0.01 mL. 

C17-0046. Concentrated aqueous HCl has a concentration of 12.1 M. Calculate the concentrations of all ions present in a solution prepared by pipetting 1.00 mL of concentrated HCl into a 100-mL volumetric flask and filling to the mark. 

Get a disposable pipet and a little rubber bulb and construct a narrow medicine dropper. Use this to transfer your sample to the NMR tube. Don t fill it much higher than about 3-4 cm. Without any solvent, this is called, of course, a neat sample. 

An alternate method that lends itself to analysis using a database is to add varying amounts of standard to a fixed volume of unknown in separate volumetric flasks. The flasks are all filled to the mark, mixed well and measured. As an example let us take a solution containing an unknown amount of Cu2+ 25.0 ml of the unknown is pipetted into each of five 50 ml volumetric flasks. Added into these flasks are 0.0 ml, 3.0 ml 5.0 ml, 7.0 ml and 10.0 ml of a 0.600 ppm solution of Cu2+. Each flask is then filled to the mark with 1.0 M ammonia solution to develop the color. The measured absorbances were 0.326, 0.418, 0.475, 0.545 and 0.635, respectively. The concentrations of each of the standards in the... 

Pipet 1 mL of the stock solution aliquot and transfer into the calibrated container. Add sufficient quantity of D5W to fill to the required volume of 120 cc. 

Step 4 Fill the pipet to well past the calibration line by releasing the squeezing pressure, as in step 4. Reevacuate the bulb if necessary. 

Give both your acid and base solutions one final shake at this point to ensure their homogeneity. Rinse the buret with 5 to 10 mL of NaOH twice, and then fill it to the top. Open the stopcock wide open to force trapped air bubbles from the stopcock and tip. Allow this excess solution to drain into a waste flask. Bring the bottom of the meniscus to the 0.00-mL line. Using a clean 25-mL pipet (volumetric), carefully place 25.00 mL of the acid solution into each of the three flasks. Add three drops of phenolphthalein indicator to each of the three flasks. 

Filter the water samples if necessary. Then prepare them for measurement by adding 1 mL of 1 N HC1 to 50 mL of each. This can be done by filling (rinse first) 50-mL volumetric flasks with the samples to the 50-mL mark and then pipetting 1.0 mL of the HCl into these flasks. Shake well. Prepare the control sample and a blank (distilled water) in the same way as the samples. 

Time-dependent mass change of low volumes of DMSO under ambient laboratory conditions. Dry DMSO was pipetted (2 or 5 gL) into the wells in alternating rows of a low-volume 384-well microplate, and the plate was incubated on the laboratory bench under ambient conditions (approximately 21°C and 35% relative humidity) and weighed periodically using an analytical balance. Filled triangles are data from wells initiated with 2-gL DMSO open squares are data from wells initiated with 5-gL DMSO. 

---