Authentic Involvement

Authentication The process used to confirm the identity of a person, or to prove the integrity of specific information. In the case of a message, authentication involves determining the message source, and providing assurance that the message has not been modified or replaced in transit (ABA). 

HPLC-ICP-MS, GC-AED, and CZE-ICP-MS offer sufficient sensitivity and selenium selectivity for the speciation of selenium compounds in many samples but do not give structural identification of known, unknown, or unpredicted compounds. This lack of identification becom es more important as more efficient separations are achieved. Chromatographic identification is based on migration time through a chromatographic support, but authentic standards of selenium compounds are often not available for retention-based identification, except for simple compounds. The major approaches to analyte authentication involve preparation of additional synthetic standards or isolation of purified selenimn compounds from sample matrixes for further characterization by electrospray (ES-MS) or matrix-assisted laser desorption ionization. 

Petersen, D. 2001. Authentic Involvement. National Safety Council NSC Press. 

Complex environmental samples originate from diverse matrices (the predominant material of which the sample to be analyzed is composed). These matrices, usually either water or soil/sediment, can contain as many as 50 to 100 organic components at widely varying concentrations. The EPA approach to the analysis of these samples involves the analysis of specific (or target) compounds and the use of authentic standards for quality control. The current number of standards in the EPA repository is about 1500, and their analysis is covered by various approved methods. 

There are several possible reasons why a scientific study of an art work may be desirable. An obvious one is in cases where the authenticity of an object is doubted on styHstic grounds, but no unanimous opinion exists. The scientist can identify the materials, analy2e the chemical composition, and then investigate whether these correspond to what has been found in comparable objects of unquestioned provenance. If the sources for the materials can be characterized, eg, through trace element composition or stmcture, it may be possible to determine whether the sources involved in the procurement of the materials for comparable objects with known provenance are the same. Comparative examination of the technological processes involved in the manufacture allows for conclusions as to whether the object was made using techniques actually available to the people who supposedly created it. Additionally, dating techniques may lead to the estabUshment of the date of manufacture. 

Anhydrotetracycline oxygenase from Streptomjces aureofaciens which cataly2es the conversion of anhydrotetracycline to dehydrotetracycline, has been isolated and characterized as a flavin-dependent oxygenase (83). It consists of two subunits of mol wt = 57, 500 based on SDS/polyacrylamide—gel electrophoresis. The cosynthetic factor 1 of Streptomjces aureofaciens involved in the reduction of 5a,lla-dehydrochlortetracycline to chlortetracycline, has been identified as 7,8-didemethyl-8-hydroxy-5-deazariboflavin. This work was aided by comparison of spectral data with that of an authentic sample obtained from the hydrolysis of coenzyme F-420 (84). 

Authenticity evaluation has recently received increased attention in a number of industries. The complex mixtures involved often require very high resolution analyses and, in the case of determining the authenticity of natural products, very accurate determination of enantiomeric purity. Juchelka et al. have described a method for the authenticity determination of natural products which uses a combination of enantioselective multidimensional gas chromatography with isotope ratio mass spectrometry (28). In isotope ratio mass spectrometry, combustion analysis is combined with mass spectrometry, and the ratio of the analyte is measured versus a... 

Mizutani and coworkers57a confirmed the presence of polychloro(methylsulfonyl)biphenyls (159-170) as sulfur-containing metabolites of chlorobiphenyls (Cl-BP) in the feces of mice based on both GLC-mass spectrometry and chemical derivatization. In some cases comparison with authentic samples (161 and 162) was also made. When preparing 161 and 162,2,5-dichloro-3-(methylsulfonyl)aniline, 2,5-dichloro-l-iodo-3-(methylsulfonyl)benzene and 2,2, 5,5 -tetrachloro-3,3 -bis(methyl-sulfonyl)biphenyl were also obtained and their four peak El mass spectra reported572. Similar data were given for the corresponding 4-substituted intermediates, which were involved in the preparation of 162. Also 2,4, 5-trichloro-2 -(methylsulfonyl)-biphenyl was prepared and its four peak mass spectra given. Metabolites 163 and 164 were also identified by comparison with the authentic standards. 

In addition to the increased precision in the communication between the researcher and the programmer, there will be an increase in the accuracy of the data involved in the research. As Mason [23] pointed out early on in the history of computer use, authenticity and correctness are necessary for accuracy. One current controversy in the pharmaceutical industry, in fact, depends on accuracy, which in turn affects liability. People in and out of the industry are discussing how best to make research visible to potential users of drugs. 

These reactions, which involve a normal SN2 displacement as depicted, represent the first authenticated examples of displacement with inversion of configuration at a cyclopropyl carbon27 31. The facility of these reactions (proceeding at temperatures below 0 °C) seems even more remarkable considering the distortion that must accompany the flattening of a cyclopropyl carbon. 

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