Weighing of solids

As with the weighing of solids on a prescription balance, there are limitations to liquid measuring devices as well. For example, assume that only one pipet having graduations from one to ten milliliters is available, and it is desired to measure one fluid ounce. In such a case, one ounce can be measured by measuring 10 mL three times. Measurement of volumes less than that of the... 

A typical HTS campaign may require hundreds of thousands of samples delivered daily. Thus it is necessary to have all neat (solid) samples in liquid form in order to prepare and deliver them quickly. The first process in compound management to support HTS is dissolution of all solid samples into solutions—a process known as solubilization that makes samples readily available for biological testing. Another advantage to centralized compound solubilization, even for post-HTS activities, is to preserve the samples and reduce waste of the crown jewels. Compound solubilization usually requires (1) selection of solvent, (2) determining concentration and volume, (3) weighing of solids, and (4) solubilization. 

Weighing of solid substances will release dust. A dust extract cabinet, equipped with a High Efficiency Particulate Air (HEPA) or Ultra Low Particulate Air (ULPA) filter (see Table 27.4) in the rear wall or in the exhaust, or both, will limit the exposure of operators to active substances. Additional options are the wearing of respirators (see Sect. 26.4.1) and a closed weighing vessel. 

Weighing of Solids in Milligram Quantities (p. 39) Technique 4 Solvent Extraction... 

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