Appropriate laboratory solution preparation

Kits. Kits for the preparation of radiopharmaceuticals are a convenient solution to synthesis of products containing short-Hved radionucHdes (eg, In, I, Tc) bound to a nonradio active moiety. The labeling step is performed either at a commercial radiopharmacy, or within the institutional nuclear medicine laboratory. The kits are usually stored as a frozen solution or lyophilized product. The material of interest is then metered out into kit dosages. The kit vials are thawed or reconstituted and mixed with the appropriate radionucHde. 

Switch on and allow the instrument to warm up the time for this will be quite short if the circuit is of the solid-state type. While this is taking place, make certain that the requisite buffer solutions for calibration of the meter are available, and if necessary prepare any required solutions this is most conveniently done by dissolving an appropriate buffer tablet (these are obtainable from many suppliers of pH meters and from laboratory supply houses) in the specified volume of distilled water. 

Orthosilicic acid, Si(OH)4, could be an appropriate precursor, but it cannot be stored in monomeric form at reasonable concentrations in aqueous solutions. It enters easily into polycondensation reactions (1) that result in its polymerization. As a monomer, the orthosilicic add exists in aqueous solutions at a concentration of less than 100 ppm [18]. This is too small to fabricate sol-gel derived materials, although diatoms and sponges have the property of concentrating silica from seawater containing only a few mg per liter [60]. Sol-gel processing in the laboratory can be performed with a rather concentrated solution of orthosilicic add. This requires freshly prepared add the procedure is time consuming which restrids its widespread use. 

Appropriate characterization has to be made of reference substances, reagents and other purchased items as well as of test samples, solutions and other preparations that are used for the laboratory activity. The supplies must meet specified requirements appropriate to their use. 

Rubidium acid salts are usually prepared from rubidium carbonate or hydroxide and the appropriate acid in aqueous solution, followed by precipitation of the crystals or evaporation to dryness. Rubidium sulfate is also prepared by the addition of a hot solution of barium hydroxide to a boiling solution of rubidium alum until all the aluminum is precipitated. The pH of the solution is 7.6 when the reaction is complete. Aluminum hydroxide and barium sulfate are removed by filtration, and rubidium sulfate is obtained by concentration and crystallization from the filtrate. Rubidium aluminum sulfate dodecahydrate [7488-54-2] (alum), RbA SO 12H20, is formed by sulfuric acid leaching of lepidolite ore. Rubidium alum is more soluble than cesium alum and less soluble than the other alkali alums. Fractional crystallization of Rb alum removes K, Na, and Li values, but concentrates the cesium value. Rubidium hydroxide, RbOH, is prepared by the reaction of rubidium sulfate and barium hydroxide in solution. The insoluble barium sulfate is removed by filtration. The solution of rubidium hydroxide can be evaporated partially in pure nickel or silver containers. Rubidium hydroxide is usually supplied as a 50% aqueous solution. Rubidium carbonate, Rb2C03, is readily formed by bubbling carbon dioxide through a solution of rubidium hydroxide, followed by evaporation to dryness in a fluorocarbon container. Other rubidium compounds can be formed in the laboratory by means of anion-exchange techniques. Table 4 lists some properties of common rubidium compounds. 

Safety glasses must be worn in the laboratory at all times. Appropriate safety gloves must be worn when preparing solutions. Caution must be used in making polymer solutions. Material safety data sheets must be read regarding the solvent, polymer, and suspected additives as many solvents and monomers are toxic, carcinogenic, or flammable. Polymer solutions should be made up at concentra-... 

The Dye-in-Polymer concept was first proposed and reduced to practice in our laboratory (12). It involves the ablative marking with an appropriate laser, of a polymer film containing a dissolved dye. The dye-in-polymer film can be easily prepared by spin-coating a dye/polymer solution onto a reflective substrate. The structure of the DIP recording medium is shown in Figure 8. 

UMEs of 10 pm in diameter and voltammetric instruments for use with such UMEs are commercially available. Electrodes of smaller dimensions can be prepared in the laboratory, although this requires considerable skill [74], In order to use UMEs successfully for high-speed voltammetry in highly resistive solutions, care must be taken concerning the effects of the ohmic drop and the capacitance of the cell system [65 b, 74, 75]. Moreover, two types of voltammograms, i.e. curves (a) and (b) in Fig. 5.23, should be used appropriately, according to the ob-... 

Because buffer solutions are widely used in the laboratory and in medicine, prepackaged buffers having a variety of precisely known pH values are commercially available (Figure 16.5). The manufacturer prepares these buffers by choosing a buffer system having an appropriate pKa value and then adjusting the amounts of the ingredients so that the [base]/[acid] ratio has the proper value. 

Many polymers, including polyethylene, polypropylene, and nylons, do not dissolve in appropriate solvents at room temperature, so membranes cannot be made by solution casting. To prepare small pieces of film, a laboratory press... 

Small Quantities. Wear butyl rubber gloves,10 laboratory coat, and eye protection. Work in the fume hood. Prepare a dilute (5%) aqueous solution of hydrazine by adding slowly to the appropriate volume of water. For each 1 g of hydrazine, place 120 mL (about 25% excess) of household laundry bleach (containing 5.25% sodium hypochlorite) into a three-necked, round-bottom flask equipped with a stirrer, thermometer, and dropping funnel. Add the aqueous hydrazine dropwise to the stirred hypochlorite solution at such a rate that the temperature is maintained at 45-50oC. The addition takes about 1 hour. Stirring is continued overnight (at least 12 hours). Wash the reaction mixture into the drain.12,13... 

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