Mixing laboratory safety

It is often not practical to use actual process fluids in the mixing laboratory, as this can involve the use of expensive and obstructive safety precautions as well as inconvenient temperatures and pressures. To avoid these problems, suitable simulant fluids must be found that will behave in a manner representative of the process fluid in the laboratory mixer. It should be noted that the simulant fluid must have the correct rheological properties for the scale at which the measurements are to be made. This is not necessarily the same as simply having the same properties as the fluid in the process for example, if it is non-Newtonian. 

Analytical chemistry is a critical component of worker safety, re-entry, and other related studies intended to assess the risk to humans during and subsequent to pesticide applications. The analytical aspect takes on added significance when such studies are intended for submission to the U.S. Environmental Protection Agency and/or other regulatory authorities and are thus required to be conducted according to the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Good Laboratory Practice (GLP) Standards, or their equivalent. This presentation will address test, control, and reference substance characterization, use-dilution (tank mix) verification, and specimen (exposure matrix sample) analyses from the perspective of GLP Standards requirements. 

Place a small pile of the mixed composition on the fireproof board, insert a section of safety fuse into the base of the pile, and carefully light the end of the fuse with a match. Step back and observe the effect. Because of the generation of smoke by most pyrotechnic compositions, these tests are best conducted outdoors or in a well-ventilated area such as a laboratory fume hood. 3e certain no flammable materials are near the test area, for sparks may be produced. 

Wear nitrile rubber gloves, laboratory coat, and eye protection. Work in the fume hood. Cover the hydride with a 1 1 1 mixture by weight of sodium or calcium carbonate, clay cat litter (bentonite), and sand. Mix carefully. Place material in a large container behind a safety shield in the hood. Slowly add dry butyl alcohol (31 mL per gram of aluminum hydride). After reaction ceases, slowly and cautiously add water (three times the volume of alcohol added). Neutralize with 6 M hydrochloric acid (prepared by adding concentrated acid to an equal volume of cold water), and let stand until solids settle. Decant the liquid into drain and discard the solid residue as normal refuse.7,8... 

A more expensive alternative is to use standard AutoAnalyser type systems, based on multichannel peristaltic pumps, to pump samples and reagents and/or diluents at the desired rates to give automatic mixing at the desired ratio. Flame photometric detectors have been used for many years with AutoAnalysers, especially in clinical laboratories. Curiously, in the past, this approach has less often been routinely used in environmental analytical laboratories employing flame spectrometry, perhaps because an attractive feature of flame spectrometry is the speed of response when used conventionally. Over the past few years, however, there has been an increasing tendency towards fully automated, unattended operation of flame spectrometers. This undoubtedly reflects, at least in part, the improvements in safety features in modern instruments, which often incorporate a comprehensive selection of fail-safe devices. It also reflects the impact of microprocessor control systems, which have greatly facilitated automation of periodic recalibration. 

Thyroid hormones are frequently affected by lithium, but rarely in a clinically significant way. Changes in certain laboratory tests of thyroid function are common but seldom require discontinuation of treatment. However, approximately 5 percent of patients develop hypothyroidism, which some clinicians elect to treat with thyroid supplementation while continuing lithium (Weber, Saklad, and Kastenhol 1992). Periodic thyroid function monitoring is important, not only from a safety standpoint but to rule out (in the bipolar individual with depressed or mixed-state features), that hypothyroidism is not the cause of symptoms. 

Biological (microbiological) safety cabinets In addition to accidental spillages, numerous laboratory procedures—pipeting, mixing, homogenizing, ultrasonic... 

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