Experiment-specific laboratory chemical

Preparation of Experiment-Specific Laboratory Chemical Safety Summaries from Material Safety Data Sheets for Undergraduate Chemistry Courses... 

OSHA mandated Material Safety Data Sheets (MSDSs) contain important safety information that should be incorporated into undergraduate chemistry instruction. Ho>vever, these documents are not well designed for the academic teaching laboratory. Additionally, there is little or no coverage of MSDSs in chemistry laboratory manuals or textbooks. One approach to the incorporation of this topic this is the introduction of a student exercise that involves the preparation of an experiment-specific laboratory chemical safety summary (LCSS) based on the LCSSs presented in the latest edition of Prudent Practices in the Laboratory (1). These one-page student-prepared summaries use information obtained from MSDSs, but are modified to the actual quantities, concentrations, and procedures used in the experiment. This approach provides beginning chemistry students with appropriate education about MSDSs. 

Plant designers are well supplied with corrosion data by materials manufacturers. These data are based on both experience and laboratory studies, but the information is usually based on specific parameters such as concentration of chemical or temperature. Edeleanu has emphasised this problem... 

Will the experiment generate any chemical that should be destroyed by a special laboratory procedure If so, what procedure or specific areas in laboratory ... 

Huff, J., Cirvello, J., Haseman, J., and Bucher, J. (1991). Chemicals associated with site-specific neoplasia in 1394 long-term carcinogenesis experiments in laboratory rodents. Environ Health Perspect 93, 247-270. 

Initiated by the chemical dynamics simulations of Bunker [37,38] for the unimolecular decomposition of model triatomic molecules, computational chemistry has had an enormous impact on the development of unimolecular rate theory. Some of the calculations have been exploratory, in that potential energy functions have been used which do not represent a specific molecule or molecules, but instead describe general properties of a broad class of molecules. Such calculations have provided fundamental information concerning the unimolecular dissociation dynamics of molecules. The goal of other chemical dynamics simulations has been to accurately describe the unimolecular decomposition of specific molecules and make direct comparisons with experiment. The microscopic chemical dynamics obtained from these simulations is the detailed information required to formulate an accurate theory of unimolecular reaction rates. The role of computational chemistry in unimolecular kinetics was aptly described by Bunker [37] when he wrote The usual approach to chemical kinetic theory has been to base one s decisions on the relevance of various features of molecular motion upon the outcome of laboratory experiments. There is, however, no reason (other than the arduous calculations involved) why the bridge between experimental and theoretical reality might not equally well start on the opposite side of the gap. In this paper... results are reported of the simulation of the motion of large numbers of triatomic molecules by... 

Prudent execution of experiments requires not only sound judgment and an accurate assessment of the risks involved in laboratory work, but also the selection of appropriate work practices to reduce risk and protect the health and safety of the laboratory workers as well as the public and the environment. Chapter 3 provides specific guidelines to enable laboratory workers to evaluate the hazards and assess the risks associated with laboratory chemicals, equipment, and operations. Chapter 4 demonstrates how to control those risks when managing the inventory of chemicals in the laboratory. How the protocols outlined in Chapter 3 are put to use in the execution of a carefully planned experiment is the subject of Chapter 5. 

Bucquet s detailed experimental histories of materials regarded as compound proximate principles of plants demonstrate impressively the diverse provenance of these substances, either firom chemical experiments in the chemical laboratory or from the world of trade and commerce. Many of his specific varieties of proximate principles of plants were imported commodities also described in the contemporary pharmacopoeias. For example, the class of extractive parts of plants (see figure 13.7) assembled various chemical extracts separated from plants in the laboratory by decoction and subsequent evaporation as well as juices prepared on a large scale in the trade, such as the juice of Hypocistis, juice of Acasia, and opium. Bucquet described not only the way to obtain the latter three pharmaceutical simplicia from... 

National Laboratory program of critical experiments providing data useful in authenticating nuclear reactor calculations and in establishing specifications for chemical processes and for transport and storage of fissile materials. Many earlier results from this program are included in Ref. 1,... 

Background Activities. Before attempting to prepare a Laboratory Chemical Safety Summary related to a specific experiment, the students were introduced to MSDSs by a series of preliminary lecture-laboratory discussions. These are outlined below ... 

It is also clear that it is difficult to relate cause and effect to any specific chemical since, with the exception of point source effluents, many waterways contain a multitude of chemicals, of which the active endocrine disruptor may not be that which has been measured in the water or tissue. For such reasons, many studies have used in vitro experiments in which isolated tissue, either from a control animal or one captured in a polluted water system, is exposed to a single pollutant in the laboratory. Such experiments have shown significant disruption to testicular activity by a wide range of xenobiotics, including cadmium, lindane, DDT, cythion, hexadrin and PCBs. ... 

If analytical methods are validated in inter-laboratory validation studies, documentation should follow the requirements of the harmonized protocol of lUPAC. " However, multi-matrix/multi-residue methods are applicable to hundreds of pesticides in dozens of commodities and have to be validated at several concentration levels. Any complete documentation of validation results is impossible in that case. Some performance characteristics, e.g., the specificity of analyte detection, an appropriate calibration range and sufficient detection sensitivity, are prerequisites for the determination of acceptable trueness and precision and their publication is less important. The LOD and LOQ depend on special instmmentation, analysts involved, time, batches of chemicals, etc., and cannot easily be reproduced. Therefore, these characteristics are less important. A practical, frequently applied alternative is the publication only of trueness (most often in terms of recovery) and precision for each analyte at each level. No consensus seems to exist as to whether these analyte-parameter sets should be documented, e.g., separately for each commodity or accumulated for all experiments done with the same analyte. In the latter case, the applicability of methods with regard to commodities can be documented in separate tables without performance characteristics. 

The ESRI experiments described in our publications and summarized in this chapter led to spatially resolved information on the effect of treatment conditions, amount of stabilizer, and polymer composition on the degradation rate. In the heterophasic systems studied in our laboratory, ESRI has identified specific morphological domains where chemical processes are accelerated. The combination of ID and 2D spectral-spatial ESRI experiments led to mapping of the stabilizer consumption on two length scales within the sample depth on the scale of a few mm, and within morphological domains on the scale of a few gm. 

Perhaps the most important application of redox chemicals in the modern laboratory is in oxidation or reduction reactions that are required as part of a preparation scheme. Such preoxidation or prereduction is also frequently required for certain instrumental procedures for which a specific oxidation state is essential in order to measure whatever property is measured by the instrument. An example in this textbook can be found in Experiment 19 (the hydroxylamine hydrochloride keeps the iron in the +2 state). Also in wastewater treatment plants, it is important to measure dissolved oxygen (DO). In this procedure, Mn(OH)2 reacts with the oxygen in basic solution to form Mn(OH)3. When acidified and in the presence of KI, iodine is liberated and titrated. This method is called the Winkler method. 

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