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United States Department of Agriculture

Agricultural Research Service

Formula Calculator

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A program written by Dr. John Bland in visual basic for calculations in mass spectrometry. The program will calculate the possible formulas for a given molecular weight. The formulas are calculated based on known chemical connectivities and not from random atom combinations. Because of this, all generated formulas will be actual compounds.

Program features:

1.)    Input a mass from 16 to 28548 (CH4 to C999H2000O99N99P99S99Cl99F99) and produce an output of up to 999 formulas.  Input a mass as the molecular weight (MW) or as an adduct, MH+, MNa+, MK+, or M-H.  The output formulas are for the non-adduct molecules. 

2.)    Input the mass tolerance (error) with the units of delta (m/z) or ppm – output changed accordingly.

3.)  Input minimum and maximum values for the number of each element and the degree of unsaturation (rings + unsaturated bonds).

4.)    Calculate formulas with up to 7 elements (excluding hydrogen) out of the list of C, O, N, P, S, Cl, F, Br, I, Si, or B (the last four elements in the min/max section can be changed to any of the elements except C, O, or N).

5.)    Sort any column in the output table by clicking on the column header (first sort is ascending, and next sort is descending order).

6.)    Output gives the number of each element chosen in the min/max section, the number of sites of unsaturation (U), the formula weight (FW), and the difference (delta or ppm) between the FW and the input mass.  If the formula contains phosphorus, the U column will have an asterisk when it is possible to have an unsaturated oxygen on the phosphorus (ie. phosphates).

7.)    Print or Copy the output formula list.  The Print button prints the input parameters in addition to the list of formulas.  The Copy button has options for the format of the copied data - formatted into a table or not (as a string of data), with data separated by tab, comma, or space.

Click here to see the new features of Version 3.9 (uploaded 10/14/07).


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Last Modified: 7/29/2016
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