Mass Spectrometry

The applet below computes high resolution molecular masses and isotope peak abundances for ions. The applet also generates a Beynon table for a given mass number. The chemical formulas included in the table have the correct mass and have a degree of unsaturation greater than -1. No other criteria are used; consequently, some implausible molecules (e.g., N₅) are sometimes listed.

Applet Name: beynon.class
Archive: beynon.jar
Version: 0.5 (May 2002)

The beynon.class applet was written by David N. Blauch (© Copyright 1999-2002).
Conditions of Use

The javax.swing classes are employed in this applet. Older browsers with outdated Java libraries may not provide the required classes (Netscape Navigator 4.77 suffers this problem). The applet loads and runs correctly under Netscape Communicator 6.2 and Internet Explorer 5.5. If your browser gives a "java.lang.NoClassDefFoundError" error, try downloading and installing the Java Plug-in.

This applet is still under development; additional refinements will be forthcoming. Known problems and the revision history are listed at the bottom of this page. Please send feedback on performance and information on problems to David N. Blauch.

Future Improvements

Isotopic abundances for M+3 and higher isotopes will be computed.
The user will be allowed to adjust elemental properties (e.g., natural abundances) and to add additional atoms.
The user will have the choice of sorting the entries in the Beynon table by formula and isotopic abundances in addition to the current sort on the high-resolution molecular mass.
When browsers supporting JDK 1.2 (without major bugs) become more widely available, subscripts will be used to display the chemical formulas.

Version 0.5 (May 2002)

Added fluorine, iodine, and phosphorus to the element list.
Introduced the option to disable the "degree of unsaturation" restriction in determining fragments for a Beynon table. When enabled, only fragments with a degree of unsaturation greater than -1 are allowed, which produces a more chemically plausible list of fragments. Determining the degree of unsaturation, however, requires knowledge of the bonding characteristics of each atom. Nitrogen and phosphorus are treated as trivalent. A compound such as NH₄⁺ has a degree of unsaturation of -0.5 (making no allowance for the charge), which passes the degree of unsaturation test. On the other hand, the PF₆^- ion has a degree of unsaturation of -1.5, which fails this test because the phosphorus is not trivalent in this compound. Thus disabling the degree of unsaturation test provides a more exhaustive list of possibilities.

Version 0.4 (April 1999)

beynon.v0.4.jar
A status dialog was added to provide feedback on the progress of the calculation of the Beynon table. The user may now cancel the calculation.

Version 0.3

Version 0.2 suffered from a bug that prevented the highest mass element from being included in the possible molecules generated for the Beynon table. This bug has been fixed.
Bounds checking has been introduced in several places to catch errors that occurred when zero or only one molecule was found for the Beynon table.

Version 0.2

The frame containing the Beynon table can now be closed.
The algorithm for computing valid molecular formulas has been improved and now executes much faster. The computation can still be time-consuming, especially a high molecular mass and large number of different elements are selected.

This applet requires a Java-enabled browser that supports JDK 1.2. For older browsers, install the Java Plug-in.

Recommended APPLET settings:

  CODE     = "beynon.Beynon.class"
  ARCHIVE  = "beynon.jar"
  NAME     = "Beynon Table"
  WIDTH    = 600
  HEIGHT   = 400

Please let me know how you like this applet. If you encounter any bugs or errors, please provide me with the specific details. I would also appreciate any suggestions for improvements.

David N. Blauch; dablauch@davidson.edu

© David N. Blauch, 1999-2002