Computerized library

Gertman, D. I. et al., Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR), 1990. 

Only the particle-beam interface produces El spectra for direct comparisons with computerized library spectra of fragmentation patterns. The other systems enable the relative molecular mass (RMM) of analytes up to 105 and above to be established. An example of an HPLC-APCI separation and identification of some benzodiazepine tranquillizers is shown in Figure 4.39. The most appropriate choice of LC-MS interface for a particular... 

GC-MS analysis has become standard practice in semiochemical research. There is, however, a real danger that information based exclusively on the results of computerized library searches without mass spectral and retention-time comparison with authentic synthetic material can be introduced into the literature. This could be problem especially in mammalian semiochemistry, because researchers often are faced with the problem of having to identify large numbers of compounds of which many may have very uninformative mass spectra. A critical reader of the original publication could still be aware of the unverified nature of some of the information, but this may not be pointed out in later references to the work. 

D. W. Hill,T. R. Kelley, and K. J. Langner, Computerized library search routine for comparing ultraviolet spectra of drugs separated by high-performance liquid chromatography, Anal. Chem. 59 (1987), 350-353. 

Fig. 6 El spectrum from an unknown elastomer extractable (A), with a best fit computerized library match (B).

M + H] and cluster ions such as [M + NH4]. Fig. 7 shows El and Cl (ammonia) spectra of a phenolic antioxidant. Note that the highest mass ion in the El spectrum is m/z 368, that which is hypothesized to be the molecular ion. The ammonia Cl spectrum shows a higher mass ion at m/z 386— which is 18 mass units higher ([M + NH4]+) and confirms the molecular weight of this analyte to be 368. Note that Cl is a thermodynamically controlled rather than a kinetically controlled process, which can result in significant variability in Cl spectra over time and between instruments. Computerized libraries of Cl mass spectra therefore have very limited utility. 

Fig. 2 El mass spectra from an unknown residual solvent in a sample of drug substance (see the chromatogram in Fig. 1), and the best fit computerized library search result (butyl acetate).

The compounds were separated on a strong anion exchange (SAX) HPLC column with a pH 4.5 ammonium formate-acetonitrile mobile phase. Molecular ions were not obtained for any of the conjugate structures due to decomposition, but the phenols were detected in all cases as the M or [M+H] ion. The phenol formed from each conjugate as a decomposition product could usually be identified by computerized library search. In SIM mode, limits of detection ranged from 0.25 ng for 4-nitrophenyl glucuronide to 51 ng for phenol. 

The proposed compound structures shown In Figure 1 are based partly on mass-spectal computerized library searches as compared to the 31,000 compound NIH/NBS library. It was also assumed that... 

A Computerized Library and Evaiuotion System for jntegrai Neutron Experiments,... 

A computerized library ot references to integral neutron eiq )eriment8 has b n developed at tiie Lawrence Radiation Laboratory at Livermore. This library serves as a data base for the systematic retrieval of documents describing diverse critical and bulk nuclear experiments. The evaluation and reduction of the physical parameters of tee experiments to a standard numerical format, and their comparison with calculated results using Monte Carlo computer codes and established libraries of neutron cross sections, will make routine appraisal euler, and also make possible improvement of neutron trwsport cal culations. 

A Computerized Library of Bibliographic Criticality Data, Brian L. Koponen- Thomas P. Wilcox (ILL) ... 

V.E. Hampel, RJ. Howerton, and J.A. Wade, A Computerized Library and Evaluation System for Integral Neutron Experiments, presented at the American Nuclear Society Meeting, Seattle, WA, 1969. Also published as Lawrence Livermore National Laboratory report UCRL-71584, Rev. 1 (1968). 

In the United States, Appendix III of the WASH 1400 study provided much of die data frequently referred to and includes failure rate ranges, event probabilities, human error rates, and some common cause information. The IEEE Standard IEEE 500 also contains failure rates and restoration times. In addition there is NUCLARR (Nuclear Computerized Library for Assessing Reliability) which is a PC-based package developed for the Nuclear Regulatory Commission and containing component failure rates and some human error data. Another US source is the NUREG publication. Some of the EPRI data are related to nuclear plant. In France, Electricity de France provides the EIReDA mechanical and electrical failure rate data base which is available for sale. In Sweden the TBook provides data on components in Nordic Nuclear Power Plants. 

The most common method of computer-assisted identification of metabolites (or the parent drug) is, in fact, not identification but rather confirmation of suspected identity. Computerized library search for the identification of metabolites in the course of study of a new drug is of limited value. It is not likely that the metabolites will be found in existing libraries. When one is studying the metabolism of a new drug, it may be worthwhile to obtain the mass spectra of all known derivatives of the drug, and perhaps even synthesize simple derivatives for just this purpose. The objective here is to learn about the compound, to establish structure-spectra correlations which should shed some light on the... 

The use of computerized library databases can assist in the matching of spectra to recorded examples (Topic H4). I (difficulties are foimd in distinguishing between two possibilities for the sample identity, then it may be necessary to consult reference texts or additional computer databases so that an exact match is found. Some databases give information that helps when working with samples that are new... 

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