Containers, for liquids

As a general rule, when working with semimicro quantities, it is best to employ pear shaped vessels (Fig. XII, 1, 1, a) and centrifuge tubes (Fig. XII, 1, 1, 6) as containers for liquids convenient capacities are 6, 10 and 20 or 26 ml. for flasks, and 1, 3, and 6 ml. for centrifuge tubes. Round-bottomed vessels of similar volumes... 

Common containers for liquid measurements include cylindrical and conical graduates for quantities of 500 mL or less, pipets for quantities of one mL or less, and a medicinal dropper for still smaller quantities. The calibration and use of medicinal droppers is explained in Chapter 2. 

To avoid loss by evaporation, the sample should be sealed in its container. For liquid samples, the container should be filled to the top with no headspace. If any matrix component is volatile, it may need to be stored at a temperature lower than room temperature and care should be taken when opening the container in the laboratory. Care should be taken not to lose any sample when transferring to another container, filter, etc. It may be important to not leave any portion of the sample behind (such as on the container walls) when transferring. It is also important to consider the cleanliness of the container or the laboratory equipment that comes into contact with the sample. 

MHz) for spin decoupling and H (61 MHz) for field locking. The container for liquid samples is shown in Figure 2.5. It consists of a normal high precision 5 mm NMR tube cut to a length of 60 mm and closed with a piston and a cap made from the machinable ceramic Macor. These probes were successfully used to study solvent exchange on solvated metal ions and metal ion complexes [14, 15]. 

Power supplies, 300-V for polyacrylamide gels 2000- to 3000-V for some applications Racks, for test tubes and microcentrifuge tubes Radiation shield, Lucite or Plexiglas Radioactive waste containers, for liquid and solid waste Razor blades... 

Containers for solid chemical waste disposal Containers for liquid organic waste disposal Corks... 

As an example of another form, co-extruded blow mouldings have been introduced to the market as containers for liquid detergents. The process used is known as sandwich blow moulding and provides a means by which recycled high density polyethylene can be incorporated again into a useful form by being employed between two layers of virgin material. 

Containers Containers for liquids consist principally of drums, pails, and cans made of steel or plastic and of bottles and vials made of plastic or glass. The chemical industry is often involved with all these containers, bnt the most frequently used packages for industrial chemicals are steel drums ancl pails. For exotic products, stainless-steel dmms and pails are available. The most common types nsed are 208-L (55-gal) drnms and 19-L (5-gal) pails. 

E. Rapkin and J. A. Gibbs, Int. J. Appl. Radiat. Isot., 14 71 (1963). Polyethylene Containers for Liquid Scintillation Spectrometry. 

Wolknann H, Gruenert R. Influence of visible light on stability of isoprenaline, epinephrine and levarterenol solutions in different containers. Part 86 contributions about the problem concerning the use of plastic containers for liquid medicinal preparations. Part 21 stability of pharmaceuticals and preparations. Pharmazie 1984 39(3) 161-163. 

The glassblowing operations employed in making Dewar flasks are not very difficult. However, since these flasks are often used as containers for liquid air, are evacuated, and are sometimes of large capacity, a detailed description of their fabrication is justified (Plate 9.1). 

Many containers for liquids are made of plastic, and there are then issues relating to the need to provide a barrier between potentially aggressive solvents and the main structural plastic from which the container is made. Hancock (1993) discusses the possible ways in which barrier systems can be incorporated into the container structure, and refers to the use of five- and six-layer structures that will meet a standardised mechanical drop test conducted at a temperature of —18°C. Mechanical strength is also tested when storing solvent-based products for six months at 50° C. 

Reduced aperture containers for liquids are usually fitted with screw caps similar to those described above for full aperture containers for dry products. The larger containers used for bulk chemicals are often fitted with additional safety devices such... 

Reclosable containers for liquid products are usually three-piece containers, the closure itself being formed with the third component. A common example is the cylindrical cone top container fitted with a screw neck to which a conventional cap is applied. Similar necks may be fitted to rectangular section containers with flat rather than conical tops. Press caps can also be used on this type of container. The principle of a press cap is essentially the same as a screw cap except that the tension which... 

Nowadays the smaller sizes of round and rectangular section containers for liquids are often fitted with plastic dispensing closures. It is also possible to produce two-piece screw top containers in aluminium in a similar manner to that in which two-piece aluminium aerosol cans are produced. In this case the base, which may be either flat or domed, is invariably constructed in aluminium so that the resultant container may be used for corrosive chemicals without further internal treatment. 

Fig. 1.21. Vial reactor used in the CFD method. 1 = Container for liquid 2 = stopper 3 packing 4 = tap 5 = syringe. A, open vial reactor B, closed vial reactor. From ref. 6.

Cylinder A container for liquids, gases, or solids under pressure. Ranges in size from aerosol containers found at home, such as spray deodorant, to the cryogenic (insulated) cylinders for nitrogen that can be approximately 24 in in diameter and 5 ft in length. Pressure ranges from a few pounds to 6000 pounds per square inch. 

Bags made of woven fabric do not generally provide sufficient containment for liquid products, so such bags often incorporate a film liner. Polyethylene is used most often, but aluminum foil or PVDC copolymers can be used to provide improved barrier ability. The liner may be a single material, or have a multilayer construction. Alternatively, the bags can be coated with PVC or latex to make them waterproof. Liners can also be used in bags for solid products. Often the liner is designed to be disposable to facilitate reuse of the bag. 

In the past, cases of this sort of crack damage in storage tanks and transportation containers for liquid ammonia, both at room temperature and at 0°C, were found in increasing numbers and simulated in laboratory experiments (Wilde 1981 Lunde 1984) (Figure 20.37). In a few cases, the formation of cracks was even observed in areas where the vapor phase has condensed and in low-temperature storage (-33°C). 

Polyesters are heterochain macromolecular substances characterized by the presence of carboxylate ester groups in the repeating units of their chains. Predominant in terms of volume and produets value are those based on poly(ethylene terephthalate) (PET), long established as basis of fibers, films, molding plasties and containers for liquids, and poly(butylene terephthalate) (PBT) largely used to produee fibers as well as for special applications in motor and electric industry.[l-3]... 

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION, Series 3 Tank Containers for Liquids and Gases — Specification and Testing, ISO I496/3-I990, Part 3, ISO, Geneva (1990). 

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