Glass and plasticware

The methods of preparation of glassware are indicated in Chapter 8, and if sterilisation is monitored as described the glassware should not be a source of contamination. Likewise plasticware is obtained from the manufacturer in a sterile condition. Usually sterilisation of plastic is achieved using ethylene oxide or irradiation procedures and vessels are supplied wrapped in cellophane. 

Contaminating microorganisms may be present in the cells when these are obtained. The procedures for obtaining primary cells should ensure the exclusion of contamination, but all cells entering the laboratory should be tested before carrying out transfer experiments in rooms being used for other cell transfers. 

Certain items, such as balanced salt solutions and versene which are heat-stable, are generally sterilised by autoclaving, but the majority of organic materials used in cell culture are filter-sterilised. For heat-sterilised materials it is generally sufficient to rely on a sterilisation indicator which should be included with each batch of materials being sterilised. Often autoclave tape is sufficient if used on each packet, but for solutions and larger containers, e.g. cans of pipettes, it is recommended that a liquid indicator is included within the bottle or can. 

A frequent debate in microbiology laboratories is whether disposable plastic pipettes are a justifiable expense or an extravagance. Initially, disposable pipettes are less expensive than reusable glass pipettes. However, costs associated with cleaning and sterilizing reusable glass pipettes may or may not be less than that associated with continued purchase of disposables. Disposable pipettes are available in individual packages sterilized prior to shipment. 

Fixed and variable volume pipettes find application in microbiology labs for preparation of dilutions as well as accurate dispensing of small (pL) volumes of reagents. Generally, fixed volume pipettes are used for routine laboratory purposes such as dilution, whereas variable volume pipettes are used in enzymatic assays requiring small-volume transfers. 

Finally, specific application glassware, such as a Cash still for measurement of volatile acidity, the aeration/oxidation apparatus for SO2, and distillation glassware are normally needed. 

Several commercially available preformulated agar media serve as the basis for much of the laboratory work discussed in Chapter 13. Where large amounts of media are prepared and utilized on a regular basis, it can be cost effective to prepare media using individual ingredients. However, most small wineries may wish to purchase preformulated media that require relatively minimal preparation prior to autoclaving and pouring. 

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Miscellaneous glass and plasticware, such as pipets, centrifuge tubes, microscope slides, and number-one cover slips. 

Phytohemagglutmin (PHA) (Gibco-BRL, Gaithersburg, MD) reconstitute as directed and add sufficient quantity to Ham s F-10 medium (usually about 1-2 mL/100 mL). Colcemid stock solution (Gibco-BRL) 10 ag/mL in phosphate-buffered saline (PBS). Miscellaneous glass and plasticware, such as pipets, centrifuge tubes, microscope slides, and number-one coverslips. 

Note For this assay, use reagent-grade chemicals with the lowest practicable Sb, As, Bi, Cd, Cu, Pb, Hg, Ag, and Sn levels, and use only high-purity water and gases. Rinse all glass- and plasticware twice with 10% nitric acid and twice with 10% hydrochloric acid, and then rinse thoroughly with High-Purity Water. 

All glass- and plasticware should be completely free of traces of detergent. 

Table 2 Concentration of example elements in laboratory glass and plasticware...

For digestion of silica-based materials only. Cannot be used with glass containers (use plasticware). In addition to laboratory coat and safety glasses, extra safety precautions are needed, e.g. gloves. In case of spillages, calcium gluconate gel is required for treatment of skin contact sites and should be available during use evacuate to hospital immediately if skin is exposed to liquid HF... 

You will be directed to use kitchen utensils in many of the demonstrations. Don t assume that this means that the chemicals are nontoxic. Use plasticware and paper plates whenever possible (you will be told when only glassware will do) and throw the paper and plastic away after use. Even inexpensive paper plates will work for many of the demonstrations if they have a thin plastic coating. If you have to use glass or ceramic utensils, wash them thoroughly and separately before any contemplated reuse with food, or, better, maintain a separate set dedicated to chemical demonstrations. You will probably do most of the demonstrations in the basement, kitchen, or bathroom, but keep the chemicals well separated from toothbrushes, foodstuffs, or counters that will come in contact with food or toothbrushes. You may cover your counters with newspaper for added protection. 

I. Contamination is a serious concern when attempting to identify low amounts of protein by MALDI-MS. Use only the highest quality reagents, HPLC grade solvents and high quality plasticware to minimize non-protein contamination. Ideally a set of glass/plasticware and reagents/buffers should... 

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