For pipets

Substituting known volumes (with significant figures appropriate for pipets and volumetric flasks) into equation 2.4... 

Using the tolerance values for pipets and volumetric flasks given in Table 4.2, the overall uncertainties in Ma and Mb are... 

The use of internal standards is somewhat controversial.115 There is agreement that an internal standard may be used as a correction for injection volume or to correct for pipetting errors. If an internal standard is included before sample hydrolysis or derivatization, it must be verified that the recovery of the internal standard peak is highly predictable. Ideally, the internal standard is unaffected by sample handling. Using an internal standard to correct for adsorptive or chemical losses is not generally approved, since the concentration of the standard may be altered by the conditions of sample preparation. An example of internal vs. external standards is given in Chapter 4. 

If SPA has shortcomings, and every assay technology does, they include its requirement for pipetting beads, which can be challenging for liquid handlers, and its use of radioisotopes. 

Idle mechanical functions of a robot can be hkened to those of the human body. The basic element is the trunk, to which is attached one or two arms which in some instruments have elbow joints. A variety of accessories can be attached to the end of the arm, such as a hand, fingers or special devices for pipetting etc. TTie range of these accessories varies between manufacturers, but they are not necessarily interchangeable between different robots. The accessories available should therefore be taken into account before choosing a robot. 

To use the pipettor, choose the proper size and place a polypropylene pipet tip firmly onto the cone as shown in Figure 1.6. Tips for pipets are... 

Fig. 5. (Opposite page) Pictorial representation of GenDecoder specialized for functional analysis of genetic information. (A) Flow chart of cell-free expression process. (B) A photograph of GenDecoder, dimensions 1.5 m (W), 0.85 m (D), and 1.8 m (H). The robot is equipped with three robotic arms for pipetting and plate transfer, one incubator for transcription and translation, maximum capacity four plates, and centrifuge for mRNA recovery after ethanol precipitation. Incubator capacity can be increased by handling plates manually. (C) Proteins in 1 pL from each translated mixture were analyzed as in Fig. 4, thus 0.2 pL of original translational mix. (Reprinted from ref. 18 with kind permission of Springer Science and Business Media.)...

Miniaturizeable, ratiometric readout normalizes for pipetting errors can be applied to kinases and phosphatases... 

Polarimeter, with one or more optical cells (complete with windows, caps, and Teflon or neoprene washers) constant-temperature control for range 10 to 50°C pycnometer 25-mL pipette for filling the pycnometer and a small pipette for filling the cell rubber bulb for pipetting 0 to 50°C thermometer 250-mL beaker gum-rubber tubing lint-free tissues for wiping cell windows 50-mL polyethylene bottles for PEG solution and excess solvent. 

Figure 2-2. Class pipettes. Pasteur pipettes (top) are designed for transferring small quantities of liquid (< 2 ml), for example, from a test tube into a spectrophotometer cuvette. Bulb (middle) or graduated (bottom) pipettes are designed for pipetting specific fixed and variable amounts of liquid respectively.

Calculate the number of cells needed for the antigen assay Each compound is tested at 4 concentrations in replicates of three three untreated samples (for each solvent) are needed for the standard curve. Each sample contains 3 x 10s C8166 cells. Twenty percent extra cells are used to allow for pipeting and for monitoring growth in a flask. The number of samples is calculated as 12/V+3.S. Thc total number of cells required is... 

Master laboratory station (MLS) for pipetting and dilution with 3 (A, B, C) 10 ml syringes... 

Salivary Specimens. Cortisol is stable in saliva for 1 week at 4 °C and for 4 months when stored frozen. Freezing of specimens is recommended because it leads to precipitation of salivary glycoproteins and leaves a nonviscous liquid for pipetting. ... 

The e N was determined for 21 hemoglobin solutions thus prepared using the methods described in Sections 2.1.2, 2.1.3, and 2.1.4. All glassware used for the iron determinations was made iron-free as far as possible. Only analytical grade chemicals (Merck) were used. For pipetting hemoglobin solutions, repeatedly calibrated Ostwald pipettes were used. Spectrophotometry was performed with the aid of one Unicam SP-500 and four... 

The mix is for 13 samples, allowing one extra sample for pipetting discrepancies. If a larger volume of DNA is necessary, adjustments can be made to the PCR mastermix (reducing the water volume), or DNA may be dispensed into the plate and allowed to dry down overnight at room temperature. The DNA is reconstituted once the PCR mastermix is added. 

When making reagent mixtures, excess should be made to allow for pipeting losses. As a rule of thumb, at least 10% extra is recommended. 

Horseplay Avoid practical jokes or other behavior which might confuse, startle or distract another worker (23). Mouth suction Do not use mouth suction for pipeting or starting a siphon (23, 32). 

Follow the preceding procedure for making general-transfer pipets, but aim for pipets with internal diameters of around 120-150pm to permit easy passage of a mouse or rat egg. 

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