New Version – March 2023 (v. 3.4.5). Updated mechanisms and their rates for all fragmentation types (EI, Tandem positive and negative mode). This program connects mass spectral peaks to their probable chemical structure origin and can be quickly invoked from the NISTMS program with the F9 key or right mouse button followed by send to MS Interpreter. It also enables the display of isotopic envelopes, chemical formula calculations and other related calculations and user interface control.

Here is the link to download MS Interpreter:

Version 3.4.* replaces all earlier versions under 32-bit and 64-bit Windows.

MS Interpreter was described in a poster in the meeting of the International Mass Spectrometry Society, Edinburgh, UK, 2003, “An Automated Method for Verifying Structure-Spectral Consistency Based on Ion Thermochemistry”

MS Interpreter ASMS presentations (PDF) are also available: ASMS 2017ASMS 2018, ASMS 2019

No documentation is available except built-in help system. Select Help/What's New from MS Interpreter menu to get a list of newly added features, or open file MSPCALC.chm

The following instructions assume that you have a earlier version of MS Interpreter installed on your PC.

1. Make sure the MS Search and MS Interpreter are not running. Open Task Manager and look for mspcalc.exe under Processes. If you find “Mspcalc.exe” or “Mspcalc.exe *32”, right-click it and select “End Process” or, if this does not work, select “End Process Tree”.
2. Extract file MSINTUNR.BAT from this package to the directory where the MS Interpreter executable (MSPCALC.EXE) is located.
3. Run MSINTUNR.BAT as Administrator. This will unregister the old MS Interpreter; this process lasts 1-3 sec.; no new application window will be open.
4. Find current Mspcalc.exe on your computer.
5. Create there a new folder OldVer for backup.
6. Move old files (qual.dll, mspcalc.ini, mspcalc.exe, mspcalc.chm, frag32.dll, ms_interpreter_isotope_table_default.itbl) to OldVer folder.
7. Unzip new files in the folder.
8. Run MSINTREG.BAT as Administrator. This will register the new MS Interpreter; this process lasts 1-3 sec.; no new application window will be open. Or you can run newly extracted file MSPCALC.EXE as Administrator and select from its menu Options/OLE Registration/RegServer.

The following instructions assume that you do not have a earlier version of MS Interpreter installed on your PC.

1. Extract files from this package to a directory on your computer.
2. Run MSINTREG.BAT as Administrator. This will register the new MS Interpreter. This process lasts 1-3 sec., no new application window will be open. Or you can run newly extracted file MSPCALC.EXE as Administrator; select from its menu Options/OLE Registration/RegServer.
3. Optionally create a shortcut to MSPACALC.EXE and name it “MS Interpreter”.

1. Run NIST MS Search (your current version).
2. Open a mass spectrum in any of the MS Search windows
3. Right-click the window and select “Send To”, “MS Interpreter” from the floating menu.

The MS Interpreter window should pop up and display the selected spectrum and (if present) the chemical structure. The Help/About box should display “MS Interpreter Version 3.4” or later.

1. Download the archive with MS Interpreter Registration program: msintreg.zip
2. Unpack the msintreg.exe file to the folder with the NIST MS Interpreter software (mspcalc.exe, frag32.dll, Qual.dll).
3. Close the NIST MS Search program
4. Run this program (msintreg.exe)
5. Restart the NIST MS Search program.

More detailed instruction is in the Readme.txt file included in the msintreg.zip archive.