This laboratory experiment demonstrates the use of graphite furnace atomic absorption spectrophotometry (GFAAS) for the determination of trace levels of Pb in bovine muscle or liver samples. The major emphasis of the experiment is to explore common interferences, first by investigating the impact of molecular spectral absorption interferences on a real-world sample, then demonstrating the susceptibility of GFAAS to chemical–physical matrix interferences. The combination of D2 arc background correction and calibration by standard additions is sufficient to reduce the magnitude of the interferences and obtain accurate Pb recoveries in these samples. This experiment also presents options for undergraduate chemistry majors to explore a number of other collateral issues related to the preparation of solid, biological samples for trace-level elemental determinations including sample decomposition, important figures of merit, and aspects of quality assurance in chemical measurements.
For decades, precoated heat-and solvent-set tissues have been the preferred method for mending certain types of library and archival materials due to their translucency and ability to be used without introducing moisture. In recent years, the adhesives long used to make these tissues became unavailable. The National Archives and Records Administration and the Library of Congress report joint testing of a variety of precoated tissues made with Lascaux 498 HV, Lascaux 303 HV, Avanse MV-100, Plextol B500, Aquazol 200, and Aquazol 500, adding to and building upon their research presented in 2015. Prepared tissues were applied to substrates using both heat-and solvent-set methods, then they underwent a variety of analytical testing. Testing assessed color change and reversibility after artificial aging, blocking of mends and fills after natural aging under pressure, and the adhesives' interactions with silver-based photographic materials. The method of applicationheat or solventdid not affect aging or testing results. The Avanse/Plextol tissues failed the color change tests. The Aquazol 200 and 500 dilutions and several Lascaux 498 HV and Lascaux 303 HV dilutions passed testing. Six successfully tested mixtures are presented, with case studies of use and recommendations for ongoing quality assurance.
RÉSUMÉ
The COVID-19 pandemic has changed many aspects of life and how work is accomplished. Travel restrictions and health concerns have hindered courier trips, making virtual condition reports and deinstallations necessary to retrieve loans. However, transmission pathways of the virus and the related viral attenuation on different materials and surfaces influence employee safety concerns when multiple people interact with surfaces, requiring quarantine periods or disinfection guidelines to be written to address these concerns. This paper illustrates how the National Archives and Records Administration (NARA) and the Victoria and Albert Museum (V&A) worked together virtually to safely return an important 1933 map to the US from England using quarantine periods.
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