Experimental procedure identification

Unfortunately, in most cases not all the available information on a reaction is given in the reaction equation in a publication, and even less so in reaction databases. To obtain a fuller picture of the reaction that was performed, the text describing the experimental procedure in the publication or a lab journal) would have to be consulted. Reaction products that are considered as trivial, such as water, alcohol, ammonia, nitrogen, etc., are generally not included in the reaction equation or mentioned in the text describing the experimental work. This poses serious problems for the automatic identification of the reaction center. It is highly desirable to have the full stoichiometry of a reaction specified in the equation. 

Certain commercial equipment, instruments, or materials are identified in this report to specify adequately the experimental procedure. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. 

Certain commercial materials and equipment are Identified In this report In order to adequately specify the experimental procedures. In no case does such Identification Imply recommendation or endorsement by the National Bureau of Standards, nor does It Imply that the material or equipment Identified Is necessarily the best available for the purpose. 

A case study of the identification of a counterfeit drug molecule is discussed in Section IX. C. This is a step-by-step discussion of the experimental procedure using FTMS to address this important issue. After the exact mass of the unknown componnd has been determined, the next step is to derive its elemental composition. The minimnm and maximum number of expected atoms present in the componnd mnst be specified in the search criteria to allow the compnter program to calculate possible elemental compositions. A nniqne fit of only one elemental composition is rarely obtained. The nnmber of possible compositions increases with the increasing nnmber of elements present and with increasing mass. However, other information, snch as the number of double bond eqnivalency and the isotopic distribution of the parent ion mass spectrnm, can be used to reduce the possible elemental compositions to a reasonable nnmber. Fnrther discussion can be fonnd in Section IX. C. 

The focus of our analyses and experimental procedures has been upon identification and quantitative determination of the atomizer component per se. Greater emphasis is placed upon the actual workplace dust level when the atomizer component has been removed by engineering controls or when it has been subtracted. 

Dupuy and coworkers have reported a direct gas chromatographic procedure for the examination of volatiles in vegetable oils (11). peanuts and peanut butters (12, 13), and rice and com products (14). When the procedure was appTTed to the analysis of flavor-scored samples, the instrumental data correlated well with sensory data (15, 16, 17), showing that food flavor can be measured by instrvmental means. Our present report provides additional evidence that the direct gas chromatographic method, when coupled with mass spectrometry for the identification of the compounds, can supply valid information about the flavor quality of certain food products. Such information can then be used to understand the mechanisms that affect flavor quality. Experimental Procedures... 

SRM 705 is the narrow molecular-weight-distribution sample the other SRM 706, by contrast, is a broad molecular-weight-distribution polymer, the result of a thermal polymerization which more closely resembles commercially available polymers. Both of these were supplied by the Dow Chemical Co. (Certain commercial equipment, instruments, or materials are identified in this paper in order to specify adequately the experimental procedure. In no case does such identification imply recommendation or endorsement by the National Bureau of Standards, nor does it imply that the material or equipment identified is necessarily the best available for the purpose.)... 

To use metabolic footprinting as a technique for high-throughput applications, benchmark spectra databases with identified peaks are required so that peak patterns obtained from MS or NMR analysis can be rapidly translated into relevant biological information. Common experimental procedures should, ideally, also be established for metabolite analysis [80] such as those existing in proteomics or transcriptomics. Nevertheless, the scientific community has only recently attempted to achieve these tasks. Several databases for identification of metabolomics signals by MS are now available, for instance, BIGG [81], BioCyc [82], MSlib [83], NIST [84], Metlin [85], and HMDB [86] databases. For a more comprehensive list of resources we refer to the review of Werner and coworkers [68]. 

The author appreciates critical review and suggestions by his colleagues) 1 L BarneS)J D Fassett and J.C Travis In order to describe adequately experimental procedures) it is necessary to identify commercial products by manufacturer s name or label In no Instance does such Identification imply endorsement by the National Bureau of Standards nor does it imply that the particular products or equipment are necessarily the best available for that purpose ... 

Analysis of In Vitro Metabolism Reactions by LC/MS. An increasingly useful approach in metabolism studies involves a preliminary in vitro metabolism study using liver or kidney microsomal preparations (9,10). When combined with LC/MS, such a preliminary study can rapidly provide information about potential metabolites expected from subsequent in vivo studies. A flow chart of a typical experimental procedure for the microsomal reaction with mass spectral identification is shown in Figure 4. The herbicide substrates are generally labeled with both 13C and 14C, which allows monitoring of the reaction by radioactivity detection, and facilitates metabolite identification based on characteristic doublet ions in the mass spectra. The entire procedure can be completed in several hours on a microgram scale, generating a survey of potential metabolites. 

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