Calculateur de Masse Moléculaire des Protéines — Formule
## Isotope Pattern Estimation
The natural isotope distribution creates characteristic patterns in mass spectra. The M+1 and M+2 peaks relative to the monoisotopic (M) peak help identify molecular formulas.
### Approximate Rules
M+1 contributions per atom: C = 1.1%, H = 0.015%, N = 0.37%, O = 0.04%, S = 0.8%
M+2 contributions: O = 0.20% each, S = 4.4% each, plus (M+1)²/200
These are approximations. Accurate patterns require full combinatorial calculation, especially for chlorine and bromine-containing compounds.
The natural isotope distribution creates characteristic patterns in mass spectra. The M+1 and M+2 peaks relative to the monoisotopic (M) peak help identify molecular formulas.
### Approximate Rules
M+1 contributions per atom: C = 1.1%, H = 0.015%, N = 0.37%, O = 0.04%, S = 0.8%
M+2 contributions: O = 0.20% each, S = 4.4% each, plus (M+1)²/200
These are approximations. Accurate patterns require full combinatorial calculation, especially for chlorine and bromine-containing compounds.
Exemple Résolu
Estimate isotope pattern for C10H14N2O3.
- M+1 = 10×1.1 + 14×0.015 + 2×0.37 + 3×0.04 = 11.0 + 0.21 + 0.74 + 0.12 = 12.07%
- M+2 = 12.07²/200 + 3×0.20 = 0.73 + 0.60 = 1.33%