Isotope Distribution Calculator and Mass Spec Plotter

Mass Spec Tools

Calculate Isotopes Chemical Formula: Calculation Method: High Resolution Low Resolution Low Resolution Fast Approximation Minimum abundance: 1% 0.1% 0.01% 0.001% 0.0001% Note: assumes neutral charge. Plot Configuration Show Plot Title: Subtitle: Low Mass: High Mass: Show Mass Labels Data table (mass intensity)

Overview

This program can calculate the isotopic distribution of a given chemical species. It can also plot either calculated or manually inputted isotopic distributions.

This program has been developed by Scientific Instrument Services as part of the Mass Spec Tools Collection. For a complete description of this program visit the Description of this Program Page. This program is still under development. If you have any comments or suggestions we would like to hear from you.

Instructions

Key in the chemical formula for which you would like to determine the isotopic distributions. Also type in the titles and the mass scale range which will be present in the final graphical output. You have the option of calculating the masses in low resolution or high resolution.

Example Chemical Formulas:

CH4

(CH3)2CHCH(CH3)2

C10H22

C6H5Cl

(CH3)2C6H4

Calculation should take upwards of a few seconds depending on the size of the chemical species.

The species is assumed neutral (mass of added/removed electrons and binding energy is not taken into account), which can have an affect on the high resolution methods.

These isotopes are supported:

• Hone (for 1H)
• Htwo (for 2H)
• Hthree (for 3H)
• Ctwelve (for 12C)
• Cthirteen (for 13C)
• Cfourteen (for 14C)
• Nfourteen (for 14N)
• Nfifteen (for 15N)

Changes:

• 2012-03-26: Molecule size limits have been increased.
• 2012-03-26: Internal changes: Code has been reimplemented but same algorithms kept. Speed and memory usage have improved.
• 2012-03-23: Added Ctwelve.
• 2009-10-13: Rounding change: abundances now round to nearest (not round down)
• 2009-10-12: Added support for some labeled isotopes (e.g. Dtwo and Dthree -- see above)
• 2000-02: Low resolution has been enabled again since we have corrected a roundoff (typically off-by-one) error that was occuring in low-resolution calculation of certain combinations of larger atoms (such as Rh). Low resolution now uses the same underlying algorithm as does high resolution. The "low resolution fast approximation" option uses basically our previous low-resolution algorithm, except that the accuracy has been increased by a factor of 10; nevertheless, some roundoff may occur in large molecules. However, for large molecules, the fast approximation algorithm is orders of magnitude faster than the standard algorithm.

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Developed by John J. Manura and David J. Manura,
© 1996-2012 Scientific Instrument Services.
Scientific Instrument Services is not responsible for any errors which may result from the use of this program. Send comments on this page