Table 3

Number of possible molecular formulas at different levels of mass accuracy and the impact of isotopic abundance accuracy. A mass spectrometer capable of 3 ppm but with 2% correct isotopic pattern outperforms even a (non-existing) mass spectrometer with 0.1 ppm mass accuracy! The results are computed for randomly selected targets, so single results vary but the trend remains. LEWIS and SENIOR check was applied. Candidates with unrelated high element counts were already excluded

without isotope abundance information
 2% isotopic abundance accuracy
 5% isotopic abundance accuracy






molecular mass [Da]
 10 ppm
 5 ppm
 3 ppm
 1 ppm
 0.1 ppm
 3 ppm
 5 ppm
150
 2
 1
 1
 1
 1
 1
 1
200
 3
 2
 2
 1
 1
 1
 1
300
 24
 11
 7
 2
 1
 1
 6
400
 78
 37
 23
 7
 1
 2
 13
500
 266
 115
 64
 21
 2
 3
 33
600
 505
 257
 155
 50
 5
 4
 36
700
 1046
 538
 321
 108
 10
 10
 97
800
 1964
 973
 599
 200
 20
 13
 111
900
 3447
 1712
 1045
 345
 32
 18
 196

Kind and Fiehn BMC Bioinformatics 2006 7:234   doi:10.1186/1471-2105-7-234