Analytical database

Chemical databases serve different purposes, such as the search for scientific and patent-related literature or retrieval of facts about chemical compounds. In analytical chemistry, the databases that are of interest are those that contain either original measurements (spectra and chromatograms) or derived data, such as concentrations or chemical structures. These data can be retrieved online via network from a host, for example, STN International. On the other hand, databases can be stored at individual PCs or in connection with an analytical instrument. 

Examples of some of the oldest analytical databases are given in Table 7.1. At present, databases that comprise several spectromet-ric methods, such as SDBS (Spectral database for organic compounds, AIST), exist and in SciFinder (CAS), several databases are combined to reveal more than 42 mUhon of spectra. Apart from representation of the analytical measurements in the computer, the coding of chemical structures is an important aspect of constructing analytical databases. 

Efficient retrieval of the analytical information depends on appropriate search strategies. To confirm a chemical structure on the basis of its spectrum, the database must contain the sought-for spectrum. Very often, however, no spectrum related to the assumed chemical structure is available, so then methods for simulation of spectra from a chemical structure are needed. 

Chemometrics Statistics and Computer Application in Analytical Chemistry, Third Edition. Matthias Otto. 2017 Wiley-VCH Verlag GmbH Co. KGaA. Published 2017 by Wiley-VCH Verlag GmbH Co. KGaA. 

Method Database /supplier Data Compounds Remarks 

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If sample patterns in a large database are each defined by just two values, a two-dimensional plot may reveal clustering that can be detected by the eye (Figure 3.1). However, in science our data often have many more than two dimensions. An analytical database might contain information on the chemical composition of samples of crude oil extracted from different oilfields. Oils are complex mixtures containing hundreds of chemicals at detectable levels thus, tire composition of an oil could not be represented by a point in a space of two dimensions. Instead, a space of several hundred dimensions would be needed. To determine how closely oils in the database resembled one another, we could plot the composition of every oil in this high-dimensional space, and then measure the distance between the points that represent two oils the distance would be a measure of the difference in composition. Similar oils would be "close together" in space,... 

The replacement of OES by AAS in Oxford in 1976 immediately called into question the long-term compatibility of the huge analytical database amassed by OES with subsequent analytical techniques. Detailed intertechnique comparisons were carried out, both in Oxford (Hatcher et al. 1980) and elsewhere (White 1981). Both pointed toward the same conclusion OES data are generally more scattered, and systematic differences of calibration occur between OES and AAS. Hatcher et al. contemplated the use of... 

General. We have studied the characterization of multicomponent materials by combining modem analytical instrumentation with a commercially available AI expert system development tool. Information generated from selected analytical databases may be accessed using TIMM, ( The Intelligent Machine Model, ) available from General Research Corp., McLean, VA. This Fortran expert system shell has enabled development of EXMAT, a heuristically-1inked network of expert systems for materials analysis. 

OPCW Central Analytical Database is available on CD ROM to States Parties of the CWC through the OPCW. 

The HP5MS column used in OPCW Bruker 640S GC/MS systems is a carefully chosen brand of capillary column, which gives retention indices very similar to those contained in OCAD (OPCW Central Analytical Database). 

Two certified floppy disks with copies of on-site OPCW Central Analytical Database (OCAD) are issued. 

The OPCW Central Analytical Database (OCAD), available for Member States to the CWC at OPCW, Johan de Wittlaan 32, 2517 JR The Hague, The Netherlands, http //www.opcw.org... 

Chemicals for which no GC/EIMS library spectra was available in the OPCW Central Analytical Database (OCAD), the Wiley Registry of Mass Spectral Data, and the NIST98-NIST/EPA/NIH Mass Spectral Library, at the time of the proficiency test... 

The OPCW Central Analytical Database (OCAD) is compiled and maintained by the OPCW Laboratory and contains analytical data of the chemicals that fall under the Chemical Weapons Convention (CWC) (1). States Parties (SPs) of the CWC and the OPCW (Organization for Prohibition of the Chemical Weapons) Laboratory submit analytical data for inclusion to the OCAD. These analytical data are peer reviewed by experts. Before the analytical data are included into the OCAD, they undergo a technical and political approval process. 

During the Preparatory Commission (PC) for the OPCW, a group of experts for the purposes of evaluating newly measured analytical data, was formed and was known as the Task Force of the Analytical Databases. These experts were nominated by their Governments and were all from the States Parties of the OPCW. The first meeting was organized by the Secretariat with the experts from those Member States that provided data, in March 1994. 

The Specialist Task Force on Analytical Databases established the mechanism of peer review of data for its inclusion into the OCAD. They also established the evaluation criteria for each type of data to be included in the OCAD, which they used as the basis for evaluating and accepting data. The Task Force reviewed each datum (spectrum) for technical validity. During the Preparatory Commission time, The Task Force recommended to the Expert Group on Inspection Procedures to approve the data the Task Force had evaluated and accepted. The PC would formally approve the data, which was later adopted by the CSP (see Figure 1). The current approval process is illustrated alongside the PC process for comparison purposes. 

After Entry into Force (EIF) of the CWC, the Director-General established a new group, named the VG, comprising the participants of the Task Force of the Analytical Databases and other experts from States Parties of the OPCW. The VG, after EIF, replaced the Task Force of the Analytical Databases. 

Figure 2. The process of the OPCW Central Analytical Database...

The on-site databases are prepared at the OPCW Laboratory for Verification activities. Two types of analytical data for on-site analytical databases are provided for an on-site inspection ... 

All the types of analytical data can be provided in hard copy if so required. At the moment, only MS data can be provided in electronic format as a searchable on-site analytical database to conduct on-site analysis. 

The OPCW Laboratory performs functional tests on the authenticated, certified, and on-site analytical databases. These are tests that verify that the analytical database is functional. So far, this procedure is fully developed for the MS analytical databases. The electronic version of OCAD (which so far consists of MS analytical data only) is tested with the NIST MS Search/Analysis program. The on-site MS analytical databases are tested using AMDIS software. A NIST or AMDIS library is created and this becomes the target library for a library search. A search is performed on a newly measured MS spectrum (raw data files) containing a number of chemicals that are present in the target library. Identification of the targeted spectrum indicates that the created library is functional. 

RULES FOR NAMING CHEMICALS IN THE OPCW CENTRAL ANALYTICAL DATABASE... 

The OPCW Laboratory prepares on-site analytical databases for use during an inspection, and the success of the process of creating the MS on-site database depends on the correctness and consistency of the chemical name. 

Proposed Mechanism for Updating the OPCW 7. Central Analytical Database, (CSP-II (EC-IV/DEC.2), dated 5 September 1997). 

Authentication and Certification Procedure for the OPCW Central Analytical Database and On-Site Databases, (C-VI/DEC.4, dated 17 May 2001). 

Criteria for the validation of new analytical data for updating the OPCW Central Analytical Database (S/147/99, dated 12 November 1999). 

Rules for naming compounds in the OPCW analytical database... 

OPCW Central analytical Database (OCAD). Version 7 from April 2004 contains 3078 GC retention indices, 2603 mass spectra, 1391 NMR spectra and 710 IR spectra (the database is free for the SPs). 

The Central OPCW Analytical Database, Technical Secretariat of the Organization for Prohibition of Chemical Weapons, The Hague, 2002, Version 5. 

RIs of OCAD (Reproduced by permission of the Organization for the Prohibition of Chemical Weapons from the OPCW Central Analytical Database.)... 

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