Equipment and Glassware

In this section, we will consider equipment this is everything other than chemicals that is used in a laboratory to enable analyses to be carried out. In the previous section, we saw how characteristics of equipment and the laboratory environment were interdependent, that care was needed, for instance, in siting equipment. In this section, the subject will be broadened and discussed in greater depth. 

There are a number of factors which contribute to the choice of a particular piece of equipment for a particular application. 

For each of these two situations, list as many things as possible that you would consider when choosing equipment. 

All equipment has limitations, for example, the amount of a substance it can detect or the accuracy with which it can make a measurement. If you attempt to make the equipment perform beyond its capabilities, it does not matter how carefully the equipment is operated, it will not be possible to get meaningful results. In terms of a particular instrument, fitness for purpose is interpreted as having appropriate performance capability to do the work required. This applies to all equipment, large or small. For example, a stirrer needs to perform the intended task satisfactorily while remaining essentially inert. There is a formal process for assessing the suitability of equipment to perform a given task - this is called Equipment Qualification or Equipment Validation. This is dealt with in Section 5.6.3. 

Suppose you need to select a stirrer to help mix some crystals in a concentrated mineral acid. Which of the following materials could be used for the stirrer so that it would not react with the acid  

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Considering the low stability of the pigments, all manipulations should be carried out in a light-protected environment. Equipment and glassware should be covered with black cloth or aluminum foil low temperatures for evaporation in the rotary evaporator or evaporation of small volumes directly under N2 or Ar should be used. Acidic pH should be avoided. Solutions and extracts should be stored at low temperatures under inert atmosphere and all procedures should be carried out as quickly as possible. 

All operations should be carried out under diffuse light equipment and glassware should be covered by a black cloth or aluminium foil. Atmosphere should be inert air should be replaced by a vacuum or inert gas such as nitrogen (N2) or argon (Ar). 

In this paper we review the techniques and applications of microwave irradiation in cycloaddition reactions. This mode ofheating requires not only appropriate micro-wave equipment and glassware, but also a new experimental outlook. A special section will focus on modifications of chemo-, regio- and stereoselectivity which result from use of microwaves, and possible explanations of this behavior will be given. 

Equipment and glassware, sample labeling, personal hygiene, and chemical contamination. 

Whilst this is not a comprehensive list of equipment and glassware, it is adequate to cover most situations. 

The common simple laboratory equipment and glassware (hot plates, beakers etc.) is supposed to be available. If special equipment, glassware or plastic ware is needed, it will be mentioned explicitly. 

Pressure rupture of even a small pieee of equipment may result in a serious explosion generating missiles travelling at high veloeity. This is an important eonsideration when using laboratory glassware or industrial glass equipment and pipework. 

Clean up all spillages immediately and check for pockets (e.g. in cracks and crevices) by monitoring Decontaminate equipment such as vacuum pumps and glassware prior to service/maintenance... 

The general layout of work benches, including hoods, was described in Chapter 2. Now comes the decision about where there should be drawers, cupboards, or other features. Small, shallow drawers, for instance, are just right for storing hydrometers and similar pieces of equipment and should be close to where these are to be used. Burets also need shallow drawers, but they must be wide. Certain pieces of glassware need fairly deep drawers. Much equipment calls for cupboards of certain sizes. 

Describe individual items of equipment and how they are connected in sufficient detail to enable unambiguous set-up. List minimum performance requirements and verification requirements, cross-referenced to the calibration section and any relevant instrument manuals. Number for later reference. For glassware, include grade where applicable (bear in mind that use of a particular grade may require justification and that proof of compliance may be required). Include environmental requirements (fume cupboards, etc.). 

These principles lead to the conclusion that each test substance requires an individual formulation. Sometimes different ingredients will be required for different concentrations to obtain the maximum rate of release. No universal vehicle is available for any route, but a number of approaches are. Any dosage preparation lab should be equipped with glassware, a stirring hot plate, a sonicator, a good homogenizer, and a stock of the basic formulating material, as detailed at the end of this chapter. 

Equipment PCR machine, scintillation counter, tabletop centrifuge, temperature-controlled water baths, equipment for horizontal and vertical electrophoresis, UV-illuminator, phosphor imager, automatic DNA sequencer, vacuum dot-blot manifold (Schleicher and Schuell). PCR 0.5 ml hot-start mbes, aerosol resistant pipette rips, autoclaved Eppendorf tubes (all from Fischer Scientific, Brightwaters, NY) and glassware, diethyl pyrocarbonate (DEPC, Sigma)-treated solutions. 

Detection and quantification of very low levels of di(2-ethylhexyl) phthalate are seriously limited by the presence of this compound as a contaminant in almost all laboratory equipment and reagents. Plastics, glassware, aluminium foil, cork, mbber, glass wool, solvents and Teflon sheets have all been found to be contaminated (Agency for Toxic Substances and Disease Registry, 1993). 

Polymer preparations should not be scaled up without a careful review and a gradual scaleup to check exotherms. This will determine the proper equipment and cooling needed before starting. All glassware should be free of cracks, and defects before using. In most cases, ordinary laboratory glassware may be used, but resin kettles are sometimes desirable on a larger scale operation. 

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