Nist standard Reference Database 1a nist 98 Mass Spectral Library with Windows Search Program (Version 7) For Use with Microsoft
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- Line 1: NAME: Molecule
- Line 7: Num Peaks: 18
- Incremental Name Search in User Libraries
Figure 8: Example of an Automated Printed Report of a User spectrum search with spectral and structural display. Substructure Information 
Figure 9: “Substructure Information” Window. The “Substructure Information” Window (Figure 9) has the name of the spectrum that was used to create the hit list displayed at the top. There are two panes below this: “Prob. Present” and “Prob. Absent”. These two panes contain a list of abbreviations for the substructures preceded by a number, which is the percent probability for the presence or absence of the structure. If you do not understand one of the abbrevia-tions, highlight it and a detailed explanation appears in the area of the Window labeled “Structure Details:”. In addition, the Window contains an area labeled “Chlorine/Bromine Info”, which gives the probabilities and numbers of chlorine and/or bromine atoms present. The results of a molecular weight estimation from the hit list is presented on the right side of the Window. Just above the molecular weight information is the “Struct. Set In Use” pane with a list box and a Customize button. The list box has the first substructure in the current set of substruc-tures displayed. The on the side of the pane drops the list box with a display of all the substructures in the current set. 
Figure 10: “Customize Set of Structures” Window. Customize – When this button is selected, the “Customize Set of Structures” Window is displayed (Figure 10). This Window is used to create a subset of the substructures to be identified. The list of all possible substructures is displayed in the “Full set of structures” pane. The list of substructures included in the present file is shown in the “Customized set” pane. The first time a customized list is created, both panes contain the same list. You may omit substructures from the “Customized set” pane or add from the "Full set of structures" pane. Either action occurs on the structures highlighted by Mouse action in the panes by selecting the appropriate button <- Omit -< or >- Add ->. The usual Windows conventions for selecting multiple items apply. After selecting the first substructure of the list, hold down the The Save and Open buttons allow the saving and retrieval of customized substructure sets. A temporary set is created by making modifications to the “Customized set” pane and selecting the OK button. This Window, as well as the “Substructure Information” Window, has a Help button, which displays a context sensitive Help screen. The algorithms used in the substructure identification are described in the Help Screen. The algorithms are based on development performed at NIST (S.E. Stein, “Chemical Substructure Identification by Mass Spectral Library Searching”, J. Am. Soc. Mass Spectrom. 1995, 6, 644-655). Use with Instrument Data Systems The automation features described in the USER SEARCH OPTIONS WINDOW section of this manual have been implemented to enhance the performance of the NIST MS Search Program when used with instrument mass spectral data systems. This feature is available to users whose data system is (1) capable of exporting spectra to the NIST format and (2) a Windows program that can be called within the data system. Implementation of the import feature has been provided on some data systems. The command string used to start or bring into focus the NIST MS Search Program for Windows is: C:\NISTMS\NIST$.EXE assuming the program is in the C:\NISTMS directory; if it is in some other directory, make the appropriate substitution. Two locator files are required to use the automation features: The first locator file must be in the same directory as the NIST MS Search Program, have the name AUTOIMP.MSP, and contain the text string describing the name and location of the second locator file, i.e.: C:\MYMSDS\DATA\FILESPEC.FIL where C:\MYMSDS is the directory in which the file, FILSPEC.FIL, resides. This file can be created with any text editor. 2. The second locator file is written each time you save spectra to a separate file. This file contains the text string that describes the name and location of the text file containing the spectrum (or spectra) in the NIST text format described later. You can specify whether the spectra in the NIST MS Search Program’s Clipboard Window are added to or replac-ed by the automatic import. An example of the contents of the second locator file is: C:\MYMSDS\DATA\DATAFILE.TXT 3 456
3 and 458 are separated by space decimal unsigned values of high and low words of the caller program’s main window handle (under Windows 3.1x the first number is always zero). This information is used for switching back. Under Windows 3.1x the 2nd line may be omitted. This second locator file is deleted each time the NIST MS Search Program is brought into focus and spectra are imported. User Libraries One of the primary features of the NIST MS Search Program is the ability to do comparisons of user-generated mass spectra and create User libraries to search against. The program allows up to fourteen User libraries. These may be searched in con-junction with the NIST/EPA/NIH Mass Spectral Main and/or Replicates Libraries, or they may be searched by themselves. A maximum of fifteen libraries can be included for search at one time. The program allows for the searching of combinations of libraries in any order. The inclusion of libraries and their order of search can be set from the “Libraries to Search and the Search Order” Window displayed with the Libs button from the different search dialog boxes. User libraries are maintained as subdirectories under the program’s root directory. The name given to the User library is the name of the subdirectory. This subdirectory will contain a number of database files and indexes that are used by the User library. These files exist in a binary format. The spectra and compound information are put in these files through the Librarian selection from the Tools option on the Menu Bar. The spectra and compound information can originate in a Text file in the NIST Text file format (see online Help). Spectra can also be entered through the program. This is done by using the “Spectrum Information” Window called with the New button on the “User Library Manager” Window. User libraries are very easy to create and maintain. You may want to create them using specific sets of spectra from the NIST/EPA/NIH Main or Replicates Library. Any spectrum in the Clipboard Window can be added to a User library. Any spec-trum in the Hit List Window can be copied to the Clipboard Window. The program can read user-submitted spectra in the JCAMP, U.S. EPA, or the NIST Text formats as well as formats of files submitted by various instrument manufacturers’ mass spectro-meter data systems. You should check with the manufacturer of your mass spectrometer’s data system to see if there is file compatibility. Instructions on building User libraries are included in the Librarian Help Screens. These also include the information necessary to add structures to User library spectra. NIST Text Format of Individual Spectra The NIST Text file format is very simple. A file can contain as many spectra as you want. Each spectrum must start with the field title “Name:”. There must be something in this field in order for the spectrum to be imported, i.e., the data file name and the scan number of the spectrum. The next required field title is “Num Peaks:”. The contents of this field must be the number of mass/intensity pairs that make up the spectrum. Optional fields with the titles of “Synonym:”, “Comments:”, “Formula:”, “MW:”, and “CAS#:” can be between the “Name:” and “Num Peaks:” fields. When a spectrum is saved to a Text file from the NIST/EPA/NIH Main or Replicates Library, it also contains fields with the names “NIST#:” and “DB#:”. The field with the name “NIST#:” is on the same line as the “CAS#:” field and sepa-rated by a semicolon (;). The mass/intensity list begins on the line following the line with the field title “Num Peaks:”. Each line of the mass/intensity list has no field title. When you create a file with all the allowable fields, each field title should be on a separate line. Use the following format. The format for each spectrum in a Text file usable by the program is as follows: Line 1: NAME: Molecule (Required, up to 511 characters) Line 2: SYNON: Alt. Name (Optional, up to 511 characters; may be repeated several times for different names) Line 3: COMMENT: Run 23, 8/8/88 (Optional, up to 511 characters) Line 4: FORMULA: C6H6 (Optional, up to 23 characters) Line 5: MW: (Optional) If the user spectrum contains a CAS registry number with its appropriate prefix (CAS: ), the display of the spectrum in the Plot, Compare, and Structure Windows will have the structure of the compound with that CAS registry number in the NIST/EPA/NIH Main Library. Line 6: CAS: 71-43-2 (Optional) The actual mass spectral data (number of peaks in the spectrum) must begin on the next line. It does not actually matter what line this is, as long as it precedes the line that starts the mass/intensity pair data. The VERY NEXT line and subsequent lines MUST contain the paired mass/intensity values. Line 7: Num Peaks: 18 (This prefix and the number of mass/intensity pairs is Required.)
(49,300), (75,180),(50,1792),(51,2052),(52,1962),(63,340), (73,160),(74,480),(75,180),(76,721),(77,1401),(78,9806),(79,651)
Faster User Libraries editing Faster spectral import from text file Editing/importing that used to take minutes now takes just seconds with v.1.7. Input spectra can contain up to 10,000 peaks. The most significant 800 peaks are retained. Long file names are recognized in the locator files (e.g. autoimp.msd) used with instrument data systems for automatic importing spectral data under MS Windows 95/98 or NT. Contacts
Joan Sauerwein National Institute of Standards and Technology Standard Reference Data Building 820, Room 113 Gaithersburg, MD 20899 Internet: srdata@nist.gov Phone: (301) 975-2208 FAX: (301) 926-0416 Website: http://www.nist.gov/srd
National Institute of Standards and Technology Building 221, Room A111 Gaithersburg, MD 20899 Internet: stephen.stein@nist.gov Phone: (301) 975-2505 FAX: (301) 926-4513
National Institute of Standards and Technology Building 221, Room A111 Gaithersburg, MD 20899 Internet: gary.mallard@nist.gov Phone: (301) 975-2562 FAX: (301) 926-4513 Download 293.42 Kb. Share with your friends:
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