Information Data Systems compounds

The Chemical Abstracts Service has institutionalized the use of graphic representations for identification of and retrieval of information about chemical compounds through their Graphical Data Stmcture (GDS) and connection table (CT). Two information packages. Messenger and STN Express, are the basis for this on-line retrieval system (42). 

Lloyd et al.1 described automation processes for compound optimization and simultaneous implementation of (1) a LIMS system to automate and track the flow of sample information, data analysis, and reporting (2) an automated data archiving system to handle a large number of LC/ MS/MS data files (3) custom software to track a large number of protocol flows and (4) workstation automation. 

FIA-MS-MS in parent or neutral loss mode on triple quad instruments can also be applied to screen mixtures of unknown compounds quite rapidly, so that compound classes can be recognised. Yet despite the information about molecular weight and the structural information by product ions, MS-data systems in their commercial form up to the mid-1990s provided no structural information for identification purposes in the form of libraries comparable with the NIST-library of El spectra in GC-MS analysis. It can be hoped that troubles arising out of the lack of computer-searchable library data for identification will be overcome with the gradual increase in trap applications in MS-MS mode. The situation in identification is set to change [36]. 

Second, considerable effort has been expended to create 13C NMR reference data systems that will enable spectroscopists to extract structural information from their experimental results by comparing them with documented spectra of related compounds data banks stored in computers have been compiled and are accessible for substructure searches (510-519). The advent of these facilities means that SCS evaluations have been-at least in principle-outstripped in an important field of their application, namely in their use for establishing molecular constitution and assigning signals. In cases of doubt one should rely... 

F. X-ray Powder Difi action Search System. Compounds that fail to crystallize may still be examined by X-ray diffraction, because non-crystalline materials, as powders, give characteristic diffraction patterns. A collection of powder diffraction patterns proves to be a very effective means by which to identify materials and indeed, one of the very earliest search systems in chemical analysis was based upon such data by Hanawalt (21) over forty years ago. The importance of these data in TSCA can be seen by examining the TSCA Inventory regulations for treatment of confidential chemicals (22). Section 710.7 of these regulations indicates that EPA intends to rely on powder diffraction data to assure the validity and seriousness of a manufacturers request for treating information on a chemical as confidential. 

Finally, a third approach has been proposed with five stages that focus on the chemical structure, DNA-reactivity, epigenetic effects, limited bioassays, and finally, the application of accelerated bioassays. These accelerated bio assays require 40 weeks and apply to the use of sensitive markers for induction of neoplasia in comparison to positive control compounds for important organs in human carcinogenesis. It enables data acquisition of the entire carcinogenesis process directed toward developing mechanistic information. This system would have the potential to replace the chronic bioassay in rodents in some circumstances and could serve a analternative to a chronic bioassay in a second species. ... 

Validation of the compounds in HTOS libraries has become an area that is receiving more attention. Because of the movement away from pools of compounds (mixtures) to discrete compounds for SAR development, quality control and quality assurance of the samples has become an issue. The issue of quality vs. quantity in HTOS has been discussed in a recent paper by MacDonald et al. (71). Bauer has described an information management system that incorporates several quality checks on the data generated by HTOS systems (72). 

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